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Sample records for lead shielding structure

  1. Radiation shielding lead shield

    International Nuclear Information System (INIS)

    Dei, Shoichi.

    1991-01-01

    The present invention concerns lead shields for radiation shielding. Shield boxes are disposed so as to surround a pipeline through which radioactive liquids, mists or like other objects are passed. Flanges are formed to each of the end edges of the shield boxes and the shield boxes are connected to each other by the flanges. Upon installation, empty shield boxes not charged with lead particles and iron plate shields are secured at first at the periphery of the pipeline. Then, lead particles are charged into the shield boxes. This attains a state as if lead plate corresponding to the depth of the box is disposed. Accordingly, operations for installation, dismantling and restoration can be conducted in an empty state with reduced weight to facilitate the operations. (I.S.)

  2. Design optimization of radiation shielding structure for lead slowing-down spectrometer system

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeong Dong; Ahn, Sang Joon; Lee, Yong Deok [Nonproliferation System Research Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Chang Je [Dept. of Nuclear Engineering, Sejong University, Seoul (Korea, Republic of)

    2015-04-15

    A lead slowing-down spectrometer (LSDS) system is a promising nondestructive assay technique that enables a quantitative measurement of the isotopic contents of major fissile isotopes in spent nuclear fuel and its pyroprocessing counterparts, such as 235U, 239Pu, 241Pu, and, potentially, minor actinides. The LSDS system currently under development at the Korea Atomic Energy Research Institute (Daejeon, Korea) is planned to utilize a high-flux (>101{sup 2n}/cm{sup 2}·s) neutron source comprised of a high-energy (30 MeV)/high-current (∼2 A) electron beam and a heavy metal target, which results in a very intense and complex radiation field for the facility, thus demanding structural shielding to guarantee the safety. Optimization of the structural shielding design was conducted using MCNPX for neutron dose rate evaluation of several representative hypothetical designs. In order to satisfy the construction cost and neutron attenuation capability of the facility, while simultaneously achieving the aimed dose rate limit (<0.06 μSv/h), a few shielding materials [high-density polyethylene (HDPE)–Borax, B{sub 4}C, and Li{sub 2}CO{sub 3}] were considered for the main neutron absorber layer, which is encapsulated within the double-sided concrete wall. The MCNP simulation indicated that HDPE-Borax is the most efficient among the aforementioned candidate materials, and the combined thickness of the shielding layers should exceed 100 cm to satisfy the dose limit on the outside surface of the shielding wall of the facility when limiting the thickness of the HDPE-Borax intermediate layer to below 5 cm. However, the shielding wall must include the instrumentation and installation holes for the LSDS system. The radiation leakage through the holes was substantially mitigated by adopting a zigzag-shape with concrete covers on both sides. The suggested optimized design of the shielding structure satisfies the dose rate limit and can be used for the construction of a facility in

  3. Design optimization of radiation shielding structure for lead slowing-down spectrometer system

    International Nuclear Information System (INIS)

    Kim, Jeong Dong; Ahn, Sang Joon; Lee, Yong Deok; Park, Chang Je

    2015-01-01

    A lead slowing-down spectrometer (LSDS) system is a promising nondestructive assay technique that enables a quantitative measurement of the isotopic contents of major fissile isotopes in spent nuclear fuel and its pyroprocessing counterparts, such as 235U, 239Pu, 241Pu, and, potentially, minor actinides. The LSDS system currently under development at the Korea Atomic Energy Research Institute (Daejeon, Korea) is planned to utilize a high-flux (>101 2n /cm 2 ·s) neutron source comprised of a high-energy (30 MeV)/high-current (∼2 A) electron beam and a heavy metal target, which results in a very intense and complex radiation field for the facility, thus demanding structural shielding to guarantee the safety. Optimization of the structural shielding design was conducted using MCNPX for neutron dose rate evaluation of several representative hypothetical designs. In order to satisfy the construction cost and neutron attenuation capability of the facility, while simultaneously achieving the aimed dose rate limit (<0.06 μSv/h), a few shielding materials [high-density polyethylene (HDPE)–Borax, B 4 C, and Li 2 CO 3 ] were considered for the main neutron absorber layer, which is encapsulated within the double-sided concrete wall. The MCNP simulation indicated that HDPE-Borax is the most efficient among the aforementioned candidate materials, and the combined thickness of the shielding layers should exceed 100 cm to satisfy the dose limit on the outside surface of the shielding wall of the facility when limiting the thickness of the HDPE-Borax intermediate layer to below 5 cm. However, the shielding wall must include the instrumentation and installation holes for the LSDS system. The radiation leakage through the holes was substantially mitigated by adopting a zigzag-shape with concrete covers on both sides. The suggested optimized design of the shielding structure satisfies the dose rate limit and can be used for the construction of a facility in the near future.

  4. Design optimization of radiation shielding structure for lead slowing-down spectrometer system

    Directory of Open Access Journals (Sweden)

    Jeong Dong Kim

    2015-04-01

    Full Text Available A lead slowing-down spectrometer (LSDS system is a promising nondestructive assay technique that enables a quantitative measurement of the isotopic contents of major fissile isotopes in spent nuclear fuel and its pyroprocessing counterparts, such as 235U, 239Pu, 241Pu, and, potentially, minor actinides. The LSDS system currently under development at the Korea Atomic Energy Research Institute (Daejeon, Korea is planned to utilize a high-flux (>1012 n/cm2·s neutron source comprised of a high-energy (30 MeV/high-current (∼2 A electron beam and a heavy metal target, which results in a very intense and complex radiation field for the facility, thus demanding structural shielding to guarantee the safety. Optimization of the structural shielding design was conducted using MCNPX for neutron dose rate evaluation of several representative hypothetical designs. In order to satisfy the construction cost and neutron attenuation capability of the facility, while simultaneously achieving the aimed dose rate limit (<0.06 μSv/h, a few shielding materials [high-density polyethylene (HDPE–Borax, B4C, and Li2CO3] were considered for the main neutron absorber layer, which is encapsulated within the double-sided concrete wall. The MCNP simulation indicated that HDPE-Borax is the most efficient among the aforementioned candidate materials, and the combined thickness of the shielding layers should exceed 100 cm to satisfy the dose limit on the outside surface of the shielding wall of the facility when limiting the thickness of the HDPE-Borax intermediate layer to below 5 cm. However, the shielding wall must include the instrumentation and installation holes for the LSDS system. The radiation leakage through the holes was substantially mitigated by adopting a zigzag-shape with concrete covers on both sides. The suggested optimized design of the shielding structure satisfies the dose rate limit and can be used for the construction of a facility in the near

  5. Radiation shielding application of lead glass

    International Nuclear Information System (INIS)

    Nathuram, R.

    2017-01-01

    Nuclear medicine and radiotherapy centers equipped with high intensity X-ray or teletherapy sources use lead glasses as viewing windows to protect personal from radiation exposure. Lead is the main component of glass which is responsible for shielding against photons. It is therefore essential to check the shielding efficiency before they are put in use. This can be done by studying photon transmission through the lead glasses. The study of photon transmission in shielding materials has been an important subject in medical physics and is potential useful in the development of radiation shielding materials

  6. Elevated gamma-rays shielding property in lead-free bismuth tungstate by nanofabricating structures

    Science.gov (United States)

    Liu, Jun-Hua; Zhang, Quan-Ping; Sun, Nan; Zhao, Yang; Shi, Rui; Zhou, Yuan-Lin; Zheng, Jian

    2018-01-01

    Radiation shielding materials have attracted much attention across academia and industry because of the increasing of nuclear activities. To achieve the materials with low toxicity but good protective capability is one of the most significant goals for personal protective articles. Here, bismuth tungstate nanostructures are controllably fabricated by a versatile hydrothermal treatment under various temperatures. The crystals structure and morphology of products are detailedly characterized with X-ray diffraction, electron microscope and specific surface area. It is noteworthy that desired Bi2WO6 nanosheets treated with 190 °C show the higher specific surface area (19.5 m2g-1) than that of the other two products. Importantly, it has a close attenuating property to lead based counterpart for low energy gamma-rays. Due to the less toxicity, Bi2WO6 nanosheets are more suitable than lead based materials to fabricate personal protective articles for shielding low energy radiations and have great application prospect as well as market potential.

  7. Study of neutron and gamma shielding by lead borate and bismuth lead borate glasses: transparent radiation shielding

    International Nuclear Information System (INIS)

    Singh, Vishwanath P.; Badiger, N.M.

    2013-01-01

    Radiation shielding for gamma and neutron is the prominent area in nuclear reactor technology, medical application, dosimetry and other industries. Shielding of these types of radiation requires an appropriate concrete with mixture of low-to-high Z elements which is an opaque medium. The transparent radiation shielding in visible light for gamma and neutron is also extremely essential in the nuclear facilities as lead window. Presently various types of lead equivalent glass oxides have been invented which are transparent as well as provide protection from radiation. In our study we have assessment of effectiveness of neutron and gamma radiation shielding of xPbO.(1-x) B 2 O 3 (x=0.15 to 0.60) and xBi 2 O 3 .(0.80-x) PbO.0.20 B 2 O 3 (x=0.10 to 0.70) transparent borate and bismuth glasses by NXCOM program. The neutron effective mass removal cross section, Σ R /ρ (cm 2 /g) of the lead, bismuth and boron oxides are given. We found invariable Σ R /ρ of various combinations of the lead borate glass for x=0.15 to 0.60 and bismuth lead borate glass for x=0.10 to 0.70. It is observed that the effective removal cross-section for fast neutron (cm -1 ) of lead borate reduces significantly whereas roughly constant for bismuth borate. The gamma mass attenuation coefficients (μ/ρ) of the glasses were also compared with possible experimental values and found comparable. High (μ/ρ) for gamma radiation of the bismuth glasses shows that it is better gamma shielding compared with lead containing glass. However lead borate glasses are better neutron shielding as the neutron removal coefficient are higher. Our investigation is very useful for nuclear reactor technology where prompt neutron of energy 17 MeV and gamma photon up to 10 MeV produced. (author)

  8. Verification of radiation exposure using lead shields

    International Nuclear Information System (INIS)

    Hayashida, Keiichi; Yamamoto, Kenyu; Azuma, Masami

    2016-01-01

    A long time use of radiation during IVR (intervention radiology) treatment leads up to an increased exposure on IVR operator. In order to prepare good environment for the operator to work without worry about exposure, the authors examined exposure reduction with the shields attached to the angiography instrument, i. e. lead curtain and lead glass. In this study, the lumber spine phantom was radiated using the instrument and the radiation leaked outside with and without shields was measured by the ionization chamber type survey meter. The meter was placed at the position which was considered to be that for IVR operator, and changed vertically 20-100 cm above X-ray focus by 10 cm interval. The radiation at the position of 80 cm above X-ray focus was maximum without shield and was hardly reduced with lead curtain. However, it was reduced with lead curtain plus lead glass. Similar reduction effects were observed at the position of 90-100 cm above X-ray focus. On the other hand, the radiation at the position of 70 cm above X-ray focus was not reduced with either shield, because that position corresponded to the gap between lead curtain and lead glass. The radiation at the position of 20-60 cm above X-ray focus was reduced with lead curtain, even if without lead glass. These results show that lead curtain and lead glass attached to the instrument can reduce the radiation exposure on IVR operator. Using these shields is considered to be one of good means for IVR operator to work safely. (author)

  9. Uranium-lead shielding for nuclear material transportation systems

    International Nuclear Information System (INIS)

    Lusk, E.C.; Miller, N.E.; Basham, S.J. Jr.

    1978-01-01

    The basis for the selection of shielding materials for spent fuel shipping containers is described with comments concerning the favorable and unfavorable aspects of steel, lead, and depleted uranium. A concept for a new type of material made of depleted uranium and lead is described which capitalizes on the best cask shielding characteristics of both materials. This cask shielding is made by filling the shielding cavity with pieces of depleted uranium and then backfilling the interstitial voids with lead. The lead would be bonded to the uranium and also to the cask shells if desired. Shielding density approaching 80 percent of that of solid uranium could be achieved, while a density of 65 percent is readily obtainable. This material should overcome the problems of the effect of lead melting in the fire accident, high thermal gradients at uranium-stainless steel interfaces and at a major reduction in cost over that of a solid uranium shielded cask. A development program is described to obtain information on the properties of the composite material to aid in design analysis and licensing and to define the fabrication techniques

  10. Decontaminating lead bricks and shielding

    International Nuclear Information System (INIS)

    Lussiez, G.W.

    1993-01-01

    Lead used for shielding is often surface contaminated with radionuclides and is therefore a Resource Conservation and Recovery Act (RCRA) D008 mixed waste. The technology-based standard for treatment is macroencapsulation. However, decontaminating and recycling the clean lead is a more attractive solution. Los Alamos National Lab. decontaminates material and equipment contaminated with radioisotopes. Decontaminating lead poses special problems because of the RCRA hazard classification and the size of the inventory, now about 100 metric tons and likely to grow substantially because of planned decommissioning operations. This lead, in the form of bricks and other shield shapes, is surface contaminated with fission products. One of the best methods for decontaminating lead is removing the thin superficial layer of contamination with an abrasive medium under pressure. For lead, a mixture of alumina with water and air at about 280 kPa (40 psig) rapidly and effectively decontaminates the lead. The abrasive medium is sprayed onto the lead in a sealed-off area. The slurry of abrasive and particles of lead falls through a floor grating and is collected in a pump. A pump sends the slurry mixture back to the spray gun, creating a continuous process

  11. Decontaminating lead bricks and shielding

    International Nuclear Information System (INIS)

    Lussiez, G.

    1994-01-01

    Lead used for shielding is often surface contaminated with radioisotopes and is therefore a RCRA D008 mixed waste. The technology-based standard for treatment is macroencapsulation. However, decontaminating and recycling the clean lead is a more attractive solution. Los Alamos National Laboratory decontaminates material and equipment contaminated with radioisotopes. Decontaminating lead poses special problems because of the RCRA hazard classification and the size of the inventory, now about 50 tons and likely to grow substantially of planned decommissioning operations. Thus lead, in the form of bricks and other shield shapes, is surface contaminated with fission products. One of the best methods for contaminated lead is removing the superficial layer of contamination with an abrasive medium under pressure. For lead, a mixture of alumina with water and air at about 40 psig rapidly and effectively decontaminates the lead. The abrasive medium is sprayed onto the lead in a scaled-off area. The slurry of abrasive and particles of lead falls through a floor and is collected in a sump. A pump sends the slurry mixture back to the spray gun, creating a continuous process. The process generates small volumes of lead slurry that can be solidified and, because it passes the TCLP, is not a mixed waste. The decontaminated lead can be released for recycling

  12. Decontaminating lead bricks and shielding

    International Nuclear Information System (INIS)

    Lussiez, G.W.

    1993-01-01

    Lead used for shielding is often surface contaminated with radioisotopes and is therefore a RCRA D008 mixed waste. The technology-based standard for treatment is macroencapsulation. However, decontaminating and recycling the clean lead is a more attractive solution. Los Alamos National Laboratory decontaminates material and equipment contaminated with radioisotopes. Decontaminating lead poses special problems because of the RCRA hazard classification and the size of the inventory, now about 50 tons and likely to grow substantially because of planned decommissioning operations. This lead, in the form of bricks and other shield shapes, is surface contaminated with fission products. One of the best methods for decontaminating lead is removing the thin superficial layer of contamination with an abrasive medium trader pressure. For lead, a mixture of alumina with water and air at about 40 psig rapidly and effectively decontaminates the lead. The abrasive medium is sprayed onto the lead in a sealed-off area. The slurry of abrasive and particles of lead falls through a floor grating and is collected in a sump. A pump sends the slurry mixture back to the spray gun, creating a continuous process. The process generates small volumes of contaminated lead slurry that can be solidified and, because it passes the TCLP, is not a mixed waste. The decontaminated lead can be released for recycling

  13. Shielding walls against ionizing radiation. Lead bricks

    International Nuclear Information System (INIS)

    1993-04-01

    The standard contains specifications for the shape and requirements set for lead bricks such that they can be used to construct radiation-shielding walls according to the building kit system. The dimensions of the bricks are selected in such a way as to permit any modification of the length, height and thickness of said shielding walls in units of 50 mm. The narrow side of the lead bricks juxtaposed to one another in a wall construction to shield against radiation have to form prismatic grooves and tongues: in this way, direct penetration by radiation is prevented. Only cuboid bricks (serial nos. 55-60 according to Table 10) do not have prismatic tongues and grooves. (orig.) [de

  14. Dosimetric evaluation of lead and tungsten eye shields in electron beam treatment

    International Nuclear Information System (INIS)

    Shiu, Almon S.; Tung, Samuel S.; Gastorf, Robert J.; Hogstrom, Kenneth R.; Morrison, William H.; Peters, Lester J.

    1996-01-01

    Purpose: The purpose of this study is to report that commercially available eye shields (designed for orthovoltage x-rays) are inadequate to protect the ocular structures from penetrating electrons for electron beam energies equal to or greater than 6 MeV. Therefore, a prototype medium size tungsten eye shield was designed and fabricated. The advantages of the tungsten eye shield over lead are discussed. Methods and Materials: Electron beams (6-9 MeV) are often used to irradiate eyelid tumors to curative doses. Eye shields can be placed under the eyelids to protect the globe. Film and thermoluminescent dosimeters (TLDs) were used within a specially constructed polystyrene eye phantom to determine the effectiveness of various commercially available internal eye shields (designed for orthovoltage x-rays). The same procedures were used to evaluate a prototype medium size tungsten eye shield (2.8 mm thick), which was designed and fabricated for protection of the globe from penetrating electrons for electron beam energy equal to 9 MeV. A mini-TLD was used to measure the dose enhancement due to electrons backscattered off the tungsten eye shield, both with or without a dental acrylic coating that is required to reduce discomfort, permit sterilization of the shield, and reduce the dose contribution from backscattered electrons. Results: Transmission of a 6 MeV electron beam through a 1.7 mm thick lead eye shield was found to be 50% on the surface (cornea) of the phantom and 27% at a depth of 6 mm (lens). The thickness of lead required to stop 6-9 MeV electron beams is impractical. In place of lead, a prototype medium size tungsten eye shield was made. For 6 to 9 MeV electrons, the doses measured on the surface (cornea) and at 6 mm (lens) and 21 mm (retina) depths were all less than 5% of the maximum dose of the open field (4 x 4 cm). Electrons backscattered off a tungsten eye shield without acrylic coating increased the lid dose from 85 to 123% at 6 MeV and 87 to 119% at

  15. Determination of 210Pb activity concentration in lead shielding

    International Nuclear Information System (INIS)

    Slivka, J.; Mrdja, D.; Varga, E.; Veskovic, M.

    2005-01-01

    210 Pb is concentrated during the separation lead from the ore and therefore it is the main pollutant of lead products. The content of this isotope limits the applicability of lead for low-level shielding of gamma spectrometers. In this paper, a new method for the determination of 210 Pb activity concentration in lead shielding from 46.5 keV gamma line intensity is presented. (author) [sr

  16. Efficiency of the cervical lead shield during intraoral radiography

    International Nuclear Information System (INIS)

    Kaffe, I.; Littner, M.M.; Shlezinger, T.; Segal, P.

    1986-01-01

    The cervical lead shield was compared with the conventional lead apron with regard to efficiency of protection against radiation during a full-month survey (fourteen periapical and two bitewing radiographs). The study was performed on a Temex tissue-equivalent human phantom, and thermoluminescent dosimetry was used to measure radiation absorption in the ovaries, testes, and thyroid gland areas. Results showed that the cervical shield significantly reduces the amount of radiation to the skin in all three areas and is equally as effective as the combination of lead apron and thyroid shield. It is therefore recommended as a protective measure during intraoral radiography

  17. Thermoforming plastic in lead shield construction

    International Nuclear Information System (INIS)

    Abrahams, M.E.; Chow, C.H.; Loyd, M.D.

    1989-01-01

    Radiation treatments using low energy X-rays or electrons frequently require a final field defining shield to be placed on the patient's skin. A custom made lead cut-out is used to provide a close fit to a particular patient's surface contours. We have developed a procedure which utilizes POLYFORM thermoplastic to obtain a negative mold of the patient instead of the traditional plaster bandage or dental impression gel. The Polyform is softened in warm water, molded carefully over the patient's surface, and is removed when set or hardened, usually within five minutes. Then lead sheet cut-outs can be formed within this negative. For shielding cut-outs requiring thicker lead sheet, a positive is made from dental stone using this Polyform negative. We have found this procedure to be neat, fast and comfortable for both patient and the dosimetrist

  18. Shielding structure analysis for LSDS facility

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hong Yeop; Kim, Jeong Dong; Lee, Yong Deok; Kim, Ho Dong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    The nuclear material (Pyro, Spent nuclear fuel) itself and the target material to generate neutrons is the LSDS system for isotopic fissile assay release of high intensity neutron and gamma rays. This research was performed to shield from various strong radiation. A shielding evaluation was carried out with a facilities model of LSDS system. The MCNPX 2.5 code was used and a shielding evaluation was performed for the shielding structure and location. The radiation dose based on the hole structure and location of the wall was evaluated. The shielding evaluation was performed to satisfy the safety standard for a normal person (1 μSv/h) and to use enough interior space. The MCNPX2.5 code was used and a dose evaluation was performed for the location of the shielding material, shielding structure, and hole structure. The evaluation result differs according to the shielding material location. The dose rate was small when the shielding material was positioned at the center. The dose evaluation result regarding the location of the shielding material was applied to the facility and the shielding thickness was determined (In 50 cm + Borax 5 cm + Out 45cm). In the existing hole structure, the radiation leak is higher than the standard. A hole structure model to prevent leakage of radiation was proposed. The general public dose limit was satisfied when using the concrete reinforcement and a zigzag structure. The shielding result will be of help to the facility shielding optimization.

  19. Shielding structure analysis for LSDS facility

    International Nuclear Information System (INIS)

    Choi, Hong Yeop; Kim, Jeong Dong; Lee, Yong Deok; Kim, Ho Dong

    2014-01-01

    The nuclear material (Pyro, Spent nuclear fuel) itself and the target material to generate neutrons is the LSDS system for isotopic fissile assay release of high intensity neutron and gamma rays. This research was performed to shield from various strong radiation. A shielding evaluation was carried out with a facilities model of LSDS system. The MCNPX 2.5 code was used and a shielding evaluation was performed for the shielding structure and location. The radiation dose based on the hole structure and location of the wall was evaluated. The shielding evaluation was performed to satisfy the safety standard for a normal person (1 μSv/h) and to use enough interior space. The MCNPX2.5 code was used and a dose evaluation was performed for the location of the shielding material, shielding structure, and hole structure. The evaluation result differs according to the shielding material location. The dose rate was small when the shielding material was positioned at the center. The dose evaluation result regarding the location of the shielding material was applied to the facility and the shielding thickness was determined (In 50 cm + Borax 5 cm + Out 45cm). In the existing hole structure, the radiation leak is higher than the standard. A hole structure model to prevent leakage of radiation was proposed. The general public dose limit was satisfied when using the concrete reinforcement and a zigzag structure. The shielding result will be of help to the facility shielding optimization

  20. Comparative study of tungsten and lead as gamma ray shielding material

    International Nuclear Information System (INIS)

    Wang Jian; Zou Shuliang

    2011-01-01

    This article firstly compares the tungsten and lead's physical properties, price and environmental performance, then calculates the thickness of tungsten and lead with the gamma ray 10% transmission when the photon energy are 0.1 MeV, 0.2 MeV, 0.5, 1 MeV and 1.25 MeV, and makes a comparison chart. Finally, it establishes a commonly used shielding model, through which to validate whether the thickness of theoretical calculation can achieve an effective shielding effect by MCNP program. The results showers that tungsten as a new type of shielding material has a lot of advantages, which shielding ability is far higher than the lead. Thus it provides the reference to choose the suitable shielding materials in special occasions. (authors)

  1. Gamma-ray shielding effect of Gd3+ doped lead barium borate glasses

    Science.gov (United States)

    Kummathi, Harshitha; Naveen Kumar, P.; Vedavathi T., C.; Abhiram, J.; Rajaramakrishna, R.

    2018-05-01

    The glasses of the batch xPbO: 10BaO: (90-x)B2O3: 0.2Gd2O3 (x = 40,45,50 mol %) were prepared by melt-quench technique. The work emphasizes on gamma ray shielding effect on doped lead glasses. The role of Boron is significant as it acts as better neutron attenuator as compared with any other materials, as the thermal neutron cross-sections are high for Gadolinium, 0.2 mol% is chosen as the optimum concentration for this matrix, as higher the concentration may lead to further increase as it produces secondary γ rays due to inelastic neutron scattering. Shielding effects were studied using Sodium Iodide (NaI) - Scintillation Gamma ray spectrometer. It was found that at higher concentration of lead oxide (PbO) in the matrix, higher the attenuation which can be co-related with density. Infra-red (I.R.) spectra reveals that the conversion of Lose triangles to tight tetrahedral structure results in enhancement of shielding properties. The Differential Scanning Calorimeter (D.S.C.) study also reveals that the increase in glass forming range increases the stability which in-turn results in inter-conversion of BO3 to BO4 units such that the density of glass increases with increase in PbO content, resulting in much stable and efficient gamma ray shielding glasses.

  2. Investigation and assessment of lead slag concrete as nuclear shields

    International Nuclear Information System (INIS)

    Zaghloul, Y.R.

    2009-01-01

    The present work is concerned with the efficiency of heavy weight concrete as a shielding material in constructing nuclear installations as well as for radioactive wastes disposal facilities.In this context, lead slag was used as a replacement for fine aggregates in heavy concrete shields that include local heavy weight aggregates (namely; barite and ilmenite) as well as normal concrete includes dolomite and sand as coarse and fine aggregates, as a reference. The effect of different percentages of lead slag was investigated to assess the produced lead slag concrete as a nuclear shielding material. The different properties (physical, mechanical and nuclear) of the produced lead slag concrete were investigated. The results obtained showed that increasing the lead slag percentage improving the investigated properties of the different concrete mixes. In addition, ilmenite concrete with 20% lead slag showed the best results for all the investigated properties.

  3. Technical products for radiation shielding. Shield assembled from lead blocks for radiation protection. General technical requirements

    International Nuclear Information System (INIS)

    1981-01-01

    The object of this standard description is the general technological requirements of 50 and 100 mm thick radiation protection shields assembled from lead blocks. The standard contains the definitions, types, parameters and dimensions of shields, their technical and acceptance criteria with testing methods, tagging, packaging, transportation and storage requirements, producer's liability. Some illustrated assembling examples, preferred parameters and dosimetry methods for shield inspection are given. (R.P.)

  4. Influence of lead apron shielding on absorbed doses from panoramic radiography.

    Science.gov (United States)

    Rottke, D; Grossekettler, L; Sawada, K; Poxleitner, P; Schulze, D

    2013-01-01

    This study investigated the absorbed doses in a full anthropomorphic body phantom from two different panoramic radiography devices, performing protocols with and without applying a lead apron. A RANDO(®) full body phantom (Alderson Research Laboratories Inc., Stamford, CT) was equipped with 110 thermoluminescent dosemeters at 55 different sites and set up in two different panoramic radiography devices [SCANORA(®) three-dimensional (3D) (SOREDEX, Tuusula, Finland) and ProMax(®) 3D (Planmeca, Helsinki, Finland)] and exposed. Two different protocols were performed in the two devices. The first protocol was performed without any lead shielding, whereas the phantom was equipped with a standard adult lead apron for the second protocol. A two-tailed paired samples t-test for the SCANORA 3D revealed that there is no difference between the protocol using lead apron shielding (m = 87.99, s = 102.98) and the protocol without shielding (m = 87.34, s = 107.49), t(54) = -0.313, p > 0.05. The same test for the ProMax 3D showed that there is also no difference between the protocol using shielding (m = 106.48, s = 117.38) and the protocol without shielding (m = 107.75, s = 114,36), t(54) = 0.938, p > 0.05. In conclusion, the results of this study showed no statistically significant differences between a panoramic radiography with or without the use of lead apron shielding.

  5. Gamma radiation shielding analysis of lead-flyash concretes

    International Nuclear Information System (INIS)

    Singh, Kanwaldeep; Singh, Sukhpal; Dhaliwal, A.S.; Singh, Gurmel

    2015-01-01

    Six samples of lead-flyash concrete were prepared with lead as an admixture and by varying flyash content – 0%, 20%, 30%, 40%, 50% and 60% (by weight) by replacing cement and keeping constant w/c ratio. Different gamma radiation interaction parameters used for radiation shielding design were computed theoretically and measured experimentally at 662 keV, 1173 keV and 1332 keV gamma radiation energy using narrow transmission geometry. The obtained results were compared with ordinary-flyash concretes. The radiation exposure rate of gamma radiation sources used was determined with and without lead-flyash concretes. - Highlights: • Concrete samples with lead as admixture were casted with flyash replacing 0%, 20%, 30%, 40%, 50% and 60% of cement content (by weight). • Gamma radiation shielding parameters of concretes for different gamma ray sources were measured. • The attenuation results of lead-flyash concretes were compared with the results of ordinary flyash concretes

  6. Radiation shielding structure for concrete structure

    International Nuclear Information System (INIS)

    Oya, Hiroshi

    1998-01-01

    Crack inducing members for inducing cracks in a predetermined manner are buried in a concrete structure. Namely, a crack-inducing member comprises integrally a shielding plate and extended plates situated at the center of a wall and inducing plates vertically disposed to the boundary portion between them with the inducing plates being disposed each in a direction perforating the wall. There are disposed integrally a pair of the inducing plate spaced at a predetermined horizontal distance on both sides of the shielding plate so as to form a substantially crank-shaped cross section and extended plates formed in the extending direction of the shielding plate, and the inducing plates are disposed each in a direction perforating the wall. Then, cracks generated when stresses are exerted can be controlled, and generation of cracks passing through the concrete structure can be prevented reliably. The reliability of a radiation shielding effect can be enhanced remarkably. (N.H.)

  7. Glasses impregnated with lead for radiation shielding

    International Nuclear Information System (INIS)

    Abd El Monem, A.M.; Kansouh, W.A.; Megahid, R.M.; Ismail, A.L.; Awad, E.M.

    2005-01-01

    The attenuation properties of glasses with different concentration of lead have been investigated for the attenuation of gamma-rays from cesium-137 and for total gamma rays using a beam of neutrons and gamma rays emitted from californium-252 source. Measurements have been performed using a gamma-ray spectrometer with Nal(T1) detector for gamma-rays emitted from 137 Cs and a neutron/gamma spectrometer with stilbene scintillator for measurement of total gamma-rays from 252 Cf neutron source. The latter applied the pulse shape discrimination technique to distinguish between recoil proton and recoil electron pulses. The obtained results given the form displayed pulse height spectra and attenuation relations which were used to derive the linear attenuation coefficient (μ), and the mass attenuation coefficient (mu/p) of the investigated glasses. In addition, calculations were performed to determine the attenuation properties of glass shields under investigation using XCOM code given by the others. A comparison of the shielding properties of these glasses with some standard shielding materials indicated that, the investigated glasses process the shielding advantages required for different nuclear technology applications

  8. Is lead shielding of patients necessary during fluoroscopic procedures? A study based on kyphoplasty

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Joshua R.; Marsh, Rebecca M.; Silosky, Michael S. [University of Colorado School of Medicine, Department of Radiology, Aurora, CO (United States)

    2018-01-15

    To determine the benefits, risks, and limitations associated with wrapping a patient with lead shielding during fluoroscopy-guided kyphoplasty procedures as a way to reduce operator radiation exposure. An anthropomorphic phantom was used to mimic a patient undergoing a kyphoplasty procedure under fluoroscopic guidance. Radiation measurements of the air kerma rate (AKR) were made at several locations and under various experimental conditions. First, AKR was measured at various angles along the horizontal plane of the phantom and at varying distances from the phantom, both with and without a lead apron wrapped around the lower portion of the phantom (referred to here as phantom shielding). Second, the effect of an operator's apron was simulated by suspending a lead apron between the phantom and the measurement device. AKR was measured for the four shielding conditions - phantom shielding only, operator apron only, both phantom shielding and operator apron, and no shielding. Third, AKR measurements were made at various heights and with varying C-arm angle. At all locations, the phantom shielding provided no substantial protection beyond that provided by an operator's own lead apron. Phantom shielding did not reduce AKR at a height comparable to that of an operator's head. Previous reports of using patient shielding to reduce operator exposure fail to consider the role of an operator's own lead apron in radiation protection. For an operator wearing appropriate personal lead apparel, patient shielding provides no substantial reduction in operator dose. (orig.)

  9. Is lead shielding of patients necessary during fluoroscopic procedures? A study based on kyphoplasty

    International Nuclear Information System (INIS)

    Smith, Joshua R.; Marsh, Rebecca M.; Silosky, Michael S.

    2018-01-01

    To determine the benefits, risks, and limitations associated with wrapping a patient with lead shielding during fluoroscopy-guided kyphoplasty procedures as a way to reduce operator radiation exposure. An anthropomorphic phantom was used to mimic a patient undergoing a kyphoplasty procedure under fluoroscopic guidance. Radiation measurements of the air kerma rate (AKR) were made at several locations and under various experimental conditions. First, AKR was measured at various angles along the horizontal plane of the phantom and at varying distances from the phantom, both with and without a lead apron wrapped around the lower portion of the phantom (referred to here as phantom shielding). Second, the effect of an operator's apron was simulated by suspending a lead apron between the phantom and the measurement device. AKR was measured for the four shielding conditions - phantom shielding only, operator apron only, both phantom shielding and operator apron, and no shielding. Third, AKR measurements were made at various heights and with varying C-arm angle. At all locations, the phantom shielding provided no substantial protection beyond that provided by an operator's own lead apron. Phantom shielding did not reduce AKR at a height comparable to that of an operator's head. Previous reports of using patient shielding to reduce operator exposure fail to consider the role of an operator's own lead apron in radiation protection. For an operator wearing appropriate personal lead apparel, patient shielding provides no substantial reduction in operator dose. (orig.)

  10. Influence of lead apron shielding on absorbed doses from cone-beam computed tomography

    International Nuclear Information System (INIS)

    Rottke, Dennis; Andersson, Jonas; Ejima, Ken-Ichiro; Sawada, Kunihiko; Schulze, Dirk

    2017-01-01

    The aim of the present work was to investigate absorbed and to calculate effective doses (EDs) in cone-beam computed tomography (CBCT). The study was conducted using examination protocols with and without lead apron shielding. A full-body male RANDO"R phantom was loaded with 110 GR200A thermoluminescence dosemeter chips at 55 different sites and set up in two different CBCT systems (CS 9500"R, ProMax"R 3D). Two different protocols were performed: the phantom was set up (1) with and (2) without a lead apron. No statistically significant differences in organ and absorbed doses from regions outside the primary beam could be found when comparing results from exposures with and without lead apron shielding. Consequently, calculating the ED showed no significant differences between the examination protocols with and without lead apron shielding. For the ProMax"R 3D with shielding, the ED was 149 μSv, and for the examination protocol without shielding 148 μSv (SD = 0.31 μSv). For the CS 9500"R, the ED was 88 and 86 μSv (SD = 0.95 μSv), respectively, with and without lead apron shielding. The results revealed no statistically significant differences in the absorbed doses between examination with and without lead apron shielding, especially in organs outside the primary beam. (authors)

  11. The evaluation of the radiation shielding ability of lead glass

    International Nuclear Information System (INIS)

    Tsuda, Keisuke; Fukushi, Masahiro; Myojoyama, Atsushi; Kitamura, Hideaki; Nakaya, Giichiro; Hassan, Nabil; Inoue, Kazumasa; Kimura, Junichi; Sawaguchi, Masato; Kinase, Sakae; Saito, Kimiaki

    2008-01-01

    Positron emission tomography (PET) scanning with the tracer 2-[F-18] Fluoro-2deoxy-D-glucose (FDG) is widely used in the clinical PET. However, the photon energy used in the PET scans is considerably higher than that of the X-rays traditionally used in the diagnoses. The radiation protection in the PET institution, therefore, is the remaining problem. Meanwhile, lead glass has attracted considerable attention as a radiation-shielding material for the PET institution. The aim of the present study was to evaluate the radiation-shielding ability of the lead glass against the positron emitters. The shielding ability evaluations were done both in the actual experiments and in the Monte Carlo simulation. The lead glass, the object of evaluation in this study, proved to have sufficient protective effect. The development and the spread of a thinner and lighter lead glass with the same effective dose transmission factor should be expected in the near future. (author)

  12. Comparison between Clinically Used Irregular Fields Shielded by Cerrobend and Standard Lead Blocks

    Directory of Open Access Journals (Sweden)

    Farajollahi A. R.

    2015-06-01

    Full Text Available Introduction: In radiation therapy centers across Iran, protection of normal tissues is usually accomplished by either Cerrobend or lead block shielding. In this study, the influence of these two shielding methods on central axis dose distribution of photon beam a Cobalt unit was investigated in clinical conditions. Materials and Methods: All measurements were performed for 60Co γ-ray beams and the Cerrobend blocks were fabricated by commercial Cerrobend materials. Standard lead block shields belonged to Cobalt unit. Data was collected through a calibrated ionization chamber, relative dosimetry systems and a TLD dosimetery. Results: Results of the percent depth dose (PDD measurements at depths of 0.5, 1, 5, 10, 15 and 20 cm for 23 different field sizes of patients with head and neck cancer showed no significant differences between lead and Cerrobend shielding methods. Measurement results of absolute dosimetry in depths of 1.5, 3, 5, 7, 10 and 12 cm also showed no significant differences between these two shielding methods. The same results were obtained by TLD dosimetry on patient skin. Conclusion: Use of melt shielding methods is a very easy and fast shield-making technique with no differences in PDD, absolute and skin dose between lead and Cerrobend block shielding methods.

  13. Influence of lead apron shielding on absorbed doses from cone-beam computed tomography.

    Science.gov (United States)

    Rottke, Dennis; Andersson, Jonas; Ejima, Ken-Ichiro; Sawada, Kunihiko; Schulze, Dirk

    2017-06-01

    The aim of the present work was to investigate absorbed and to calculate effective doses (EDs) in cone-beam computed tomography (CBCT). The study was conducted using examination protocols with and without lead apron shielding. A full-body male RANDO® phantom was loaded with 110 GR200A thermoluminescence dosemeter chips at 55 different sites and set up in two different CBCT systems (CS 9500®, ProMax® 3D). Two different protocols were performed: the phantom was set up (1) with and (2) without a lead apron. No statistically significant differences in organ and absorbed doses from regions outside the primary beam could be found when comparing results from exposures with and without lead apron shielding. Consequently, calculating the ED showed no significant differences between the examination protocols with and without lead apron shielding. For the ProMax® 3D with shielding, the ED was 149 µSv, and for the examination protocol without shielding 148 µSv (SD = 0.31 µSv). For the CS 9500®, the ED was 88 and 86 µSv (SD = 0.95 µSv), respectively, with and without lead apron shielding. The results revealed no statistically significant differences in the absorbed doses between examination with and without lead apron shielding, especially in organs outside the primary beam. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Radiation shielding plate

    International Nuclear Information System (INIS)

    Kobayashi, Torakichi; Sugawara, Takeo.

    1983-01-01

    Purpose: To reduce the weight and stabilize the configuration of a radiation shielding plate which is used in close contact with an object to be irradiated with radiation rays. Constitution: The radiation shielding plate comprises a substrate made of lead glass and a metallic lead coating on the surface of the substrate by means of plating, vapor deposition or the like. Apertures for permeating radiation rays are formed to the radiation shielding plate. Since the shielding plate is based on a lead glass plate, a sufficient mechanical strength can be obtained with a thinner structure as compared with the conventional plate made of metallic lead. Accordingly, if the shielding plate is disposed on a soft object to be irradiated with radiation rays, the object and the plate itself less deform to obtain a radiation irradiation pattern with distinct edges. (Moriyama, K.)

  15. Characterization of a lead breast shielding for dose reduction in computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Correia, Paula Duarte; Brochi, Marco Aurelio Corte; Azevedo-Marques, Paulo Mazzoncini de, E-mail: pauladuarte@usp.br [Universidade de Sao Paulo (FM/RSP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina; Granzotti, Cristiano Roberto Fabri; Santos, Yago da Silva [Universidade de Sao Paulo (FFCLRP/RSP), Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras

    2014-07-15

    Objective: several studies have been published regarding the use of bismuth shielding to protect the breast in computed tomography (CT) scans and, up to the writing of this article, only one publication about barium shielding was found. The present study was aimed at characterizing, for the first time, a lead breast shielding. Materials and methods: the percentage dose reduction and the influence of the shielding on quantitative imaging parameters were evaluated. Dose measurements were made on a CT equipment with the aid of specific phantoms and radiation detectors. A processing software assisted in the qualitative analysis evaluating variations in average CT number and noise on images. Results: the authors observed a reduction in entrance dose by 30% and in CTDIvol by 17%. In all measurements, in agreement with studies in the literature, the utilization of cotton fiber as spacer object reduced significantly the presence of artifacts on the images. All the measurements demonstrated increase in the average CT number and noise on the images with the presence of the shielding. Conclusion: as expected, the data observed with the use of lead shielding were of the same order as those found in the literature about bismuth shielding. (author)

  16. Comparison between steel and lead shieldings for radiotherapy rooms regarding neutron doses to patients

    International Nuclear Information System (INIS)

    Silva, M.G.; Rebello, W.F.; Andrade, E.R.; Medeiros, M.P.C.; Mendes, R.M.S.; Braga, K.L.; Gomes, R.G.

    2015-01-01

    The NCRP Report No. 151, Structural Shielding Design and Evaluation for Megavoltage X- and Gamma-Ray Radiotherapy Facilities, considers, in shielding calculations for radiotherapy rooms, the use of lead and/or steel to be applied on bunker walls. The NCRP Report calculations were performed foreseeing a better protection of people outside the radiotherapy room. However, contribution of lead and steel to patient dose should be taken into account for radioprotection purposes. This work presents calculations performed by MCNPX code in analyzing the Ambient Dose Equivalent due to neutron, H *(10) n , within a radiotherapy room, in the patients area, considering the use of additional shielding of 1 TVL of lead or 1 TVL of steel, positioned at the inner faces of walls and ceiling of a bunker. The head of the linear accelerator Varian 2100/2300 C/D was modeled working at 18MeV, with 5 x 5 cm 2 , 10 x 10 cm 2 , 20 x 20 cm 2 , 30 x 30 cm 2 and 40 x 40 cm 2 openings for jaws and MLC and operating in eight gantry's angles. This study shows that the use of lead generates an average value of H *(10) n at patients area, 8.02% higher than the expected when using steel. Further studies should be performed based on experimental data for comparison with those from MCNPX simulation. (author)

  17. Dosimetric perturbations of a lead shield for surface and interstitial high-dose-rate brachytherapy

    International Nuclear Information System (INIS)

    Candela-Juan, Cristian; Granero, Domingo; Vijande, Javier; Ballester, Facundo; Perez-Calatayud, Jose; Rivard, Mark J

    2014-01-01

    In surface and interstitial high-dose-rate brachytherapy with either 60 Co, 192 Ir, or 169 Yb sources, some radiosensitive organs near the surface may be exposed to high absorbed doses. This may be reduced by covering the implants with a lead shield on the body surface, which results in dosimetric perturbations. Monte Carlo simulations in Geant4 were performed for the three radionuclides placed at a single dwell position. Four different shield thicknesses (0, 3, 6, and 10 mm) and three different source depths (0, 5, and 10 mm) in water were considered, with the lead shield placed at the phantom surface. Backscatter dose enhancement and transmission data were obtained for the lead shields. Results were corrected to account for a realistic clinical case with multiple dwell positions. The range of the high backscatter dose enhancement in water is 3 mm for 60 Co and 1 mm for both 192 Ir and 169 Yb. Transmission data for 60 Co and 192 Ir are smaller than those reported by Papagiannis et al (2008 Med. Phys. 35 4898–4906) for brachytherapy facility shielding; for 169 Yb, the difference is negligible. In conclusion, the backscatter overdose produced by the lead shield can be avoided by just adding a few millimetres of bolus. Transmission data provided in this work as a function of lead thickness can be used to estimate healthy organ equivalent dose saving. Use of a lead shield is justified. (paper)

  18. Radiation shielding and effective atomic number studies in different types of shielding concretes, lead base and non-lead base glass systems for total electron interaction: A comparative study

    International Nuclear Information System (INIS)

    Kurudirek, Murat

    2014-01-01

    Highlights: • Radiation shielding calculations for concretes and glass systems. • Assigning effective atomic number for the given materials for total electron interaction. • Glass systems generally have better shielding ability than concretes. - Abstract: Concrete has been widely used as a radiation shielding material due to its extremely low cost. On the other hand, glass systems, which make everything inside visible to observers, are considered as promising shielding materials as well. In the present work, the effective atomic numbers, Z eff of some concretes and glass systems (industrial waste containing glass, Pb base glass and non-Pb base glass) have been calculated for total electron interaction in the energy region of 10 keV–1 GeV. Also, the continuous slowing down approximation (CSDA) ranges for the given materials have been calculated in the wide energy region to show the shielding effectiveness of the given materials. The glass systems are not only compared to different types of concretes but also compared to the lead base glass systems in terms of shielding. Moreover, the obtained results for total electron interaction have been compared to the results for total photon interaction wherever possible. In general, it has been observed that the glass systems have superior properties than most of the concretes over the high-energy region with respect to the electron interaction. Also, glass systems without lead show better electron stopping than lead base glasses at some energy regions as well. Along with the photon attenuation capability, it is seen that Fly Ash base glass systems have not only greater electron stopping capability but also have greater photon attenuation especially in high energy region when compared with standard shielding concretes

  19. Radiation shielding and effective atomic number studies in different types of shielding concretes, lead base and non-lead base glass systems for total electron interaction: A comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Kurudirek, Murat, E-mail: mkurudirek@gmail.com

    2014-12-15

    Highlights: • Radiation shielding calculations for concretes and glass systems. • Assigning effective atomic number for the given materials for total electron interaction. • Glass systems generally have better shielding ability than concretes. - Abstract: Concrete has been widely used as a radiation shielding material due to its extremely low cost. On the other hand, glass systems, which make everything inside visible to observers, are considered as promising shielding materials as well. In the present work, the effective atomic numbers, Z{sub eff} of some concretes and glass systems (industrial waste containing glass, Pb base glass and non-Pb base glass) have been calculated for total electron interaction in the energy region of 10 keV–1 GeV. Also, the continuous slowing down approximation (CSDA) ranges for the given materials have been calculated in the wide energy region to show the shielding effectiveness of the given materials. The glass systems are not only compared to different types of concretes but also compared to the lead base glass systems in terms of shielding. Moreover, the obtained results for total electron interaction have been compared to the results for total photon interaction wherever possible. In general, it has been observed that the glass systems have superior properties than most of the concretes over the high-energy region with respect to the electron interaction. Also, glass systems without lead show better electron stopping than lead base glasses at some energy regions as well. Along with the photon attenuation capability, it is seen that Fly Ash base glass systems have not only greater electron stopping capability but also have greater photon attenuation especially in high energy region when compared with standard shielding concretes.

  20. Comparison between steel and lead shieldings for radiotherapy rooms regarding neutron doses to patients

    Energy Technology Data Exchange (ETDEWEB)

    Silva, M.G.; Rebello, W.F.; Andrade, E.R.; Medeiros, M.P.C.; Mendes, R.M.S.; Braga, K.L.; Gomes, R.G., E-mail: eng.cavaliere@gmail.com, E-mail: ggrprojetos@gmail.com [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Secao de Engenharia Nuclear; Silva, A.X., E-mail: ademir@con.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    The NCRP Report No. 151, Structural Shielding Design and Evaluation for Megavoltage X- and Gamma-Ray Radiotherapy Facilities, considers, in shielding calculations for radiotherapy rooms, the use of lead and/or steel to be applied on bunker walls. The NCRP Report calculations were performed foreseeing a better protection of people outside the radiotherapy room. However, contribution of lead and steel to patient dose should be taken into account for radioprotection purposes. This work presents calculations performed by MCNPX code in analyzing the Ambient Dose Equivalent due to neutron, H *(10){sub n}, within a radiotherapy room, in the patients area, considering the use of additional shielding of 1 TVL of lead or 1 TVL of steel, positioned at the inner faces of walls and ceiling of a bunker. The head of the linear accelerator Varian 2100/2300 C/D was modeled working at 18MeV, with 5 x 5 cm{sup 2}, 10 x 10 cm{sup 2}, 20 x 20 cm{sup 2}, 30 x 30 cm{sup 2} and 40 x 40 cm{sup 2} openings for jaws and MLC and operating in eight gantry's angles. This study shows that the use of lead generates an average value of H *(10){sub n} at patients area, 8.02% higher than the expected when using steel. Further studies should be performed based on experimental data for comparison with those from MCNPX simulation. (author)

  1. Shield structure for a nuclear reactor

    International Nuclear Information System (INIS)

    Rouse, C.A.; Simnad, M.T.

    1979-01-01

    An improved nuclear reactor shield structure is described for use where there are significant amounts of fast neutron flux above an energy level of approximately 70 keV. The shield includes structural supports and neutron moderator and absorber systems. A portion at least of the neutron moderator material is magnesium oxide either alone or in combination with other moderator materials such as graphite and iron. (U.K.)

  2. Use of lead shielding on pregnant patients undergoing CT scans: Results of an international survey

    Energy Technology Data Exchange (ETDEWEB)

    Iball, Gareth R., E-mail: gri@medphysics.leeds.ac.u [Department of Medical Physics and Engineering, Old Medical School, Leeds General Infirmary, Leeds, W. Yorkshire LS1 3EX (United Kingdom); Brettle, David S. [Department of Medical Physics and Engineering, Old Medical School, Leeds General Infirmary, Leeds, W. Yorkshire LS1 3EX (United Kingdom)

    2011-05-15

    Aim: An online survey has been used to assess the use of abdominal lead shielding on pregnant patients undergoing CT scans. The aim of the study was to identify potential geographical variations in the use of such shielding as well as the opinions of the users in terms of the weight, manoeuvrability and ergonomics of the lead shields. Materials and methods: The online questionnaire was distributed to CT Radiographers in the UK, Europe, North America and Australia and responses were gathered electronically over a six month period. All completed responses were downloaded and subsequently analysed for each geographical region. Results: In total, 390 completed questionnaires were received with over 100 from each of the UK, North America and Australia. The use of lead shielding was found to vary significantly across the globe with the highest usage in North America (94.5%) and the lowest usage in Europe (46.3%). Approximately 20% of all respondents said that they experienced occupationally related back pain and 25% of all respondents said that patients complained about the weight of the shielding. Conclusion: Significant geographical variations in both the use of lead shielding for foetal radiation protection and the users' opinions of the shielding devices that are used have been identified and it has become clear that existing shielding solutions are not optimised for this task.

  3. Study of x-ray medical mitigation with lead and aluminium shield

    International Nuclear Information System (INIS)

    Malheiros, Emiliane A.; Ramos, Roberto Paulo B.; Oliveira, Ezequias Fernandes

    2016-01-01

    In this work, lead and aluminum as shielding materials and their variations in the spectra emitted by the X-ray equipment through the use of a computer program that determines the photon fluence . The study of the primary beam for power spectra used in the practice of diagnostic radiology allows you to analyze data representative of the average transmission and fluency for the studied materials. So we seek to analyze the transmission curves of lead and aluminum, as well as its influence on the thickness of shielding and changing the radiation spectrum characteristics X in the transmission of photons. (author)

  4. Evaluation of additional lead shielding in protecting the physician from radiation during cardiac interventional procedures

    International Nuclear Information System (INIS)

    Chida, Koichi; Zuguchi, Masayuki; Morishima, Yoshiaki; Katahira, Yoshiaki; Chiba, Hiroo

    2005-01-01

    Since cardiac interventional procedures deliver high doses of radiation to the physician, radiation protection for the physician in cardiac catheterization laboratories is very important. One of the most important means of protecting the physician from scatter radiation is to use additional lead shielding devices, such as tableside lead drapes and ceiling-mounted lead acrylic protection. During cardiac interventional procedures (cardiac IVR), however, it is not clear how much lead shielding reduces the physician dose. This study compared the physician dose [effective dose equivalent (EDE) and dose equivalent (DE)] with and without additional shielding during cardiac IVR. Fluoroscopy scatter radiation was measured using a human phantom, with an ionization chamber survey meter, with and without additional shielding. With the additional shielding, fluoroscopy scatter radiation measured with the human phantom was reduced by up to 98%, as compared with that without. The mean EDE (whole body, mean±SD) dose to the operator, determined using a Luxel badge, was 2.55±1.65 and 4.65±1.21 mSv/year with and without the additional shielding, respectively (p=0.086). Similarly, the mean DE (lens of the eye) to the operator was 15.0±9.3 and 25.73±5.28 mSv/year, respectively (p=0.092). In conclusion, although tableside drapes and lead acrylic shields suspended from the ceiling provided extra protection to the physician during cardiac IVR, the reduction in the estimated physician dose (EDE and DE) during cardiac catheterization with additional shielding was lower than we expected. Therefore, there is a need to develop more ergonomically useful protection devices for cardiac IVR. (author)

  5. Normalization of shielding structure quality and the method of its studying

    International Nuclear Information System (INIS)

    Bychkov, Ya.A.; Lavdanskij, P.A.

    1987-01-01

    Method for evaluation of nuclear facility radiation shield quality is suggested. Indexes of shielding structure radiation efficiency and face efficiency are used as the shielding structure quality indexes. The first index is connected with radiation dose rate during personnel irradiation behind the shield, and the second one - with the stresses in shielding structure introduction of the indexes presented allows to evaluate objectively the quality of nuclear facility shielding structure quality design construction and operation and to economize labour and material resources

  6. Shielding ability of lead loaded radiation resistant gloves

    International Nuclear Information System (INIS)

    Kawano, Takao; Ebihara, Hiroshi

    1990-01-01

    The shielding ability of radiation resistant gloves were examined. The gloves are made of lead loaded (as PbO 2 ) polyvinyl chloride resin and are about 0.4 mm of thickness (70 mg/cm 2 ). Eleven test pieces were sampled from each of three gloves (total were thirty three) and the transmission rates for radiations (X-ray or γ-ray) through the test pieces were measured with radiation sources, 99m Tc, 57 Co, 133 Ba, 133 Xe and 241 Am. The differences of the transmission rate for radiations by the positions of the gloves were smaller than 15%, and the differences by three gloves were smaller than 5% in the case of 60 keV and 141 keV radiations. The average transmission rates for radiations in thirty three test pieces were about 40% for 30 keV radiation, about 90% for 80 keV and 140 keV radiations. The shielding characteristic of the gloves could be equivalent to about 0.026 mm thick lead plate. (author)

  7. Magnetic shielding structure optimization design for wireless power transmission coil

    Science.gov (United States)

    Dai, Zhongyu; Wang, Junhua; Long, Mengjiao; Huang, Hong; Sun, Mingui

    2017-09-01

    In order to improve the performance of the wireless power transmission (WPT) system, a novel design scheme with magnetic shielding structure on the WPT coil is presented in this paper. This new type of shielding structure has great advantages on magnetic flux leakage reduction and magnetic field concentration. On the basis of theoretical calculation of coil magnetic flux linkage and characteristic analysis as well as practical application feasibility consideration, a complete magnetic shielding structure was designed and the whole design procedure was represented in detail. The simulation results show that the coil with the designed shielding structure has the maximum energy transmission efficiency. Compared with the traditional shielding structure, the weight of the new design is significantly decreased by about 41%. Finally, according to the designed shielding structure, the corresponding experiment platform is built to verify the correctness and superiority of the proposed scheme.

  8. Evaluation of Shielding Wall Optimization in Lead Slowing Down Spectrometer System

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Ju Young; Kim, Jeong Dong; Lee, Yong Deok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    A Lead Slowing Down Spectrometer (LSDS) system is nondestructive technology for analyzing isotope fissile content in spent fuel and pyro processed material, in real time and directly. The high intensity neutron and gamma ray were generated from a nuclear material (Pyro, Spent nuclear fuel), electron beam-target reaction and fission of fissile material. Therefore, shielding analysis of LSDS system should be carried out. In this study, Borax, B{sub 4}C, Li{sub 2}Co{sub 3}, Resin were chosen for shielding analysis. The radiation dose limit (<0.1 μSv/hr) was adopted conservatively at the outer wall surface. The covering could be able to reduce the concrete wall thickness from 5cm to 15cm. The optimized shielding walls evaluation will be used as an important data for future real LSDS facility design and shielding door assessment.

  9. Test of magnetic shielding cases for a 3'' phototube attached to a lead glass counter

    International Nuclear Information System (INIS)

    Ogawa, K.; Sumiyoshi, T.; Takasaki, F.

    1985-09-01

    Effect of a magnetic shielding for a phototube of 3'' diameter attached to a lead glass counter has been studied using permalloy shielding cases with two kinds of shapes. Both cases show sufficient shielding effect with magnetic field up to around 30 gauss. (author)

  10. Radiation dose reduction to the male gonads during MDCT: the effectiveness of a lead shield.

    Science.gov (United States)

    Hohl, Christian; Mahnken, Andreas H; Klotz, Ernst; Das, Marco; Stargardt, Achim; Mühlenbruch, Georg; Schmidt, Thorsten; Günther, Rolf W; Wildberger, Joachim E

    2005-01-01

    Our study was designed to quantify the effect of a standard gonad shield on the testicular radiation exposure due to scatter during routine abdominopelvic MDCT. Routine abdominopelvic MDCT was performed in 34 patients with gonadal lead shielding and 32 patients without this shielding; the testes were not exposed to the direct beam during the examination. We estimated the testicular dose administered with thermoluminescent dosimetry, taking into account each patient's body weight and body mass index (BMI). With a 1-mm lead shield, the mean testicular dose was reduced from 2.40 to 0.32 mSv, a reduction of 87%. The difference was found to be statistically significant (p Shielding the male gonads reduces the testicular radiation dose during abdominopelvic MDCT significantly and can be recommended for routine use.

  11. Radiation shielding wall structure

    International Nuclear Information System (INIS)

    Nishimura, Yoshitaka; Oka, Shinji; Kan, Toshihiko; Misato, Takeshi.

    1990-01-01

    A space between a pair of vertical steel plates laterally disposed in parallel at an optional distance has a structure of a plurality of vertically extending tranks partitioned laterally by vertically placed steel plates. Then, cements are grouted to the tranks. Strip-like steel plates each having a thickness greater than the gap between the each of the vertically placed steel plates and the cement are bonded each at the surface for each of the vertically placed steel plates opposing to the cements. A protrusion of a strip width having radiation shielding performance substantially identical with that by the thickness of the cement is disposed in the strip-like steel plates. With such a constitution, a safety radiation shielding wall structure with no worry of radiation intrusion to gaps, if formed, between the steel plates and the grouted cements due to shrinkage of the cements. (I.N.)

  12. Multifunctional Hot Structure Heat Shield

    Data.gov (United States)

    National Aeronautics and Space Administration — This project is performing preliminary development of a Multifunctional Hot Structure (HOST) heat shield for planetary entry. Results of this development will...

  13. Radiation attenuation by lead and nonlead materials used in radiation shielding garments

    International Nuclear Information System (INIS)

    McCaffrey, J. P.; Shen, H.; Downton, B.; Mainegra-Hing, E.

    2007-01-01

    The attenuating properties of several types of lead (Pb)-based and non-Pb radiation shielding materials were studied and a correlation was made of radiation attenuation, materials properties, calculated spectra and ambient dose equivalent. Utilizing the well-characterized x-ray and gamma ray beams at the National Research Council of Canada, air kerma measurements were used to compare a variety of commercial and pre-commercial radiation shielding materials over mean energy ranges from 39 to 205 keV. The EGSnrc Monte Carlo user code cavity.cpp was extended to provide computed spectra for a variety of elements that have been used as a replacement for Pb in radiation shielding garments. Computed air kerma values were compared with experimental values and with the SRS-30 catalogue of diagnostic spectra available through the Institute of Physics and Engineering in Medicine Report 78. In addition to garment materials, measurements also included pure Pb sheets, allowing direct comparisons to the common industry standards of 0.25 and 0.5 mm 'lead equivalent'. The parameter 'lead equivalent' is misleading, since photon attenuation properties for all materials (including Pb) vary significantly over the energy spectrum, with the largest variations occurring in the diagnostic imaging range. Furthermore, air kerma measurements are typically made to determine attenuation properties without reference to the measures of biological damage such as ambient dose equivalent, which also vary significantly with air kerma over the diagnostic imaging energy range. A single material or combination cannot provide optimum shielding for all energy ranges. However, appropriate choice of materials for a particular energy range can offer significantly improved shielding per unit mass over traditional Pb-based materials

  14. Radiation exposure to foetus and breasts from dental X-ray examinations: effect of lead shields.

    Science.gov (United States)

    Kelaranta, Anna; Ekholm, Marja; Toroi, Paula; Kortesniemi, Mika

    2016-01-01

    Dental radiography may involve situations where the patient is known to be pregnant or the pregnancy is noticed after the X-ray procedure. In such cases, the radiation dose to the foetus, though low, needs to be estimated. Uniform and widely used guidance on dental X-ray procedures during pregnancy are presently lacking, the usefulness of lead shields is unclear and practices vary. Upper estimates of radiation doses to the foetus and breasts of the pregnant patient were estimated with an anthropomorphic female phantom in intraoral, panoramic, cephalometric and CBCT dental modalities with and without lead shields. The upper estimates of foetal doses varied from 0.009 to 6.9 μGy, and doses at the breast level varied from 0.602 to 75.4 μGy. With lead shields, the foetal doses varied from 0.005 to 2.1 μGy, and breast doses varied from 0.002 to 10.4 μGy. The foetal dose levels without lead shielding were dental radiographic examination.

  15. Radiation shielding bricks

    International Nuclear Information System (INIS)

    Crowe, G.J.W.

    1983-01-01

    A radiation shielding brick for use in building dry walls to form radiation proof enclosures and other structures is described. It is square in shape and comprises a sandwich of an inner layer of lead or similar shielding material between outer layers of plastics material, for structural stability. The ability to mechanically interlock adjacent bricks is provided by shaping the edges as cooperating external and internal V-sections. Relatively leak-free joints are ensured by enlarging the width of the inner layer in the edge region. (author)

  16. Impact and structural analysis of the INEL 55 gallon recycled shielded storage container

    International Nuclear Information System (INIS)

    Richins, W.D.

    1996-07-01

    The INEL Recycled Shielded Storage Containers (RSSC) are designed primarily for the transportation and storage of mixed RH-TRU solid waste using recycled, potentially contaminated lead and stainless steel construction materials. Two versions of the RSSC have been developed accommodating either 30 or 55 gallon drums. This report addresses the structural qualification of the 55 gallon version of the RSSC to DOT 7A Type A requirements. The controlling qualification test is a 4 ft drop onto a rigid surface. During and after this test, the container contents must remain within the container and shielding must not be reduced. The container is also designed to withstand stacking, internal pressure, lifting loads, tiedown failure, penetration, and a range of temperatures. Nonlinear dynamic finite element analyses were performed using a range of material properties. Loads in the major connections and strains in the stainless steel and lead were monitored as a function of time during impact analyses for three simulated drop orientations. Initial results were used to develop the final design. For the final design, the stainless steel and lead have maximum strains well below ultimate levels except at an impact corner where additional deformation is acceptable. The predicted loads in the connections indicate that some yielding will occur but the containment and shielding will remain intact. The results presented here provide assurance that the container will pass the DOT 7A Type A drop tests as well as the other structural requirements

  17. Fabrication of indigenous lead-free low cost bilayer radiation protective apron and dosimetric analysis for effective shielding

    International Nuclear Information System (INIS)

    Senthilkumar, S.

    2014-01-01

    Protective aprons play a key role in the radiation protection of personnel in radiology departments. They are worn in examination rooms during radiological examinations and their specific function is to provide shielding against secondary radiation. Practically, they are used for a variety of diagnostic imaging procedures including angiography, fluoroscopy, mobiles and theatre, and are designed to shield approximately 75% of radiosensitive red bone marrow. For many years, the protective aprons play a key role in the radiation protection of personnel in imaging departments was made of lead. However, lead garments must be treated as hazardous waste for disposal and are heavy, causing back strain and other orthopedic problems for those who must wear them for long periods of time. They are worn in examination rooms during radiological examinations and their specific function is to provide shielding against secondary radiation. Originally, protective aprons consisted of lead-impregnated vinyl or rubber with a shielding equivalent given in millimetres of lead. The main purpose of this study was to fabricate light weight low cost non lead based bilayered radiation protective aprons

  18. Induced Radioactivity in Lead Shielding at the National Synchrotron Light Source.

    Science.gov (United States)

    Ghosh, Vinita J; Schaefer, Charles; Kahnhauser, Henry

    2017-06-01

    The National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory was shut down in September 2014. Lead bricks used as radiological shadow shielding within the accelerator were exposed to stray radiation fields during normal operations. The FLUKA code, a fully integrated Monte Carlo simulation package for the interaction and transport of particles and nuclei in matter, was used to estimate induced radioactivity in this shielding and stainless steel beam pipe from known beam losses. The FLUKA output was processed using MICROSHIELD® to estimate on-contact exposure rates with individually exposed bricks to help design and optimize the radiological survey process. This entire process can be modeled using FLUKA, but use of MICROSHIELD® as a secondary method was chosen because of the project's resource constraints. Due to the compressed schedule and lack of shielding configuration data, simple FLUKA models were developed. FLUKA activity estimates for stainless steel were compared with sampling data to validate results, which show that simple FLUKA models and irradiation geometries can be used to predict radioactivity inventories accurately in exposed materials. During decommissioning 0.1% of the lead bricks were found to have measurable levels of induced radioactivity. Post-processing with MICROSHIELD® provides an acceptable secondary method of estimating residual exposure rates.

  19. Evaluation of radiation shielding rate of lead aprons in nuclear medicine

    Energy Technology Data Exchange (ETDEWEB)

    Han, Sang Hyun; Han, Beom Heui; Lee, Sang Ho [Dept. of Radiological Science, Seonam University, Asan (Korea, Republic of); Hong, Dong Heui [Dept. of Radiological Science, Far East University, Eumseong (Korea, Republic of); Kim, Gi Jin [Dept. of Nuclear Medicine, Konyang University Hospital, Daejeon (Korea, Republic of)

    2017-03-15

    Considering that the X-ray apron used in the department of radiology is also used in the department of nuclear medicine, the study aimed to analyze the shielding rate of the apron according to types of radioisotopes, thus γ ray energy, to investigate the protective effects. The radioisotopes used in the experiment were the top 5 nuclides in usage statistics {sup 99m}Tc, {sup 18}F, {sup 131}I, {sup 123}I, and {sup 201}Tl, and the aprons were lead equivalent 0.35 mmPb aprons currently under use in the department of nuclear medicine. As a result of experiments, average shielding rates of aprons were {sup 99m}Tc 31.59%, {sup 201}Tl 68.42%, and {sup 123}I 76.63%. When using an apron, the shielding rate of {sup 13}'1I actually resulted in average dose rate increase of 33.72%, and {sup 18}F showed an average shielding rate of –0.315%, showing there was almost no shielding effect. As a result, the radioisotopes with higher shielding rate of apron was in the descending order of {sup 123}I, {sup 201}Tl, {sup 99m}Tc, {sup 18}F, {sup 131}I. Currently, aprons used in the nuclear medicine laboratory are general X-ray aprons, and it is thought that it is not appropriate for nuclear medicine environment that utilizes γ rays. Therefore, development of nuclear medicine exclusive aprons suitable for the characteristics of radioisotopes is required in consideration of effective radiation protection and work efficiency of radiation workers.

  20. Building with electromagnetic shield structure for individual floors

    International Nuclear Information System (INIS)

    Takahashi, T.; Nakamura, M.; Yabana, Y.; Ishikawa, T.; Nagata, K.

    1991-01-01

    This invention relates to a building having a floor-by-floor electromagnetic shield structure well-suited for application to an information network system in which an electromagnetically shielded space is divided by individual floors and electric waves are utilized within the building on a floor-by-floor basis. (author). 8 figs

  1. Building with electromagnetic shield structure for individual floors

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, T; Nakamura, M; Yabana, Y; Ishikawa, T; Nagata, K

    1991-09-10

    This invention relates to a building having a floor-by-floor electromagnetic shield structure well-suited for application to an information network system in which an electromagnetically shielded space is divided by individual floors and electric waves are utilized within the building on a floor-by-floor basis. (author). 8 figs.

  2. The shielding performance of multilayer composite shielding structures to 14.8 MeV fast neutrons

    International Nuclear Information System (INIS)

    Shen Zhiqiang; Kang Qing; Xu Jun; Wang Zhenggang; Lu Nan

    2014-01-01

    Cement-based round thin-layer samples mixed with 30% quality content of barite, and 20% quality content of carbide boron has Prepared, the same-diameter sliced samples of pure graphite and pure polyethylene has cut, then, samples combination and cross stack order has designed, formed four species Multilayer Composite shield structure, at last, neutron attenuation measurements has been done by experimental system of using 14.8 MeV neutrons from the 5SDH-2 accelerator and long counter composition, penetrating rate of samples and the shield structure to 14.8 MeV fast neutron has tested, and attenuation section has calculated. Results show that 14.8 MeV fast neutrons to higher penetration rates of thin layer samples, attenuation cross section of samples distinguish small between each other, must be increasing the thickness of the samples to reduce the experimental uncertainty; through composed of attenuation cross section and thickness parameters of composite structure, can more accurately predict the shielding ability of composite structures, error between calculation results and experimental results in 4%. (authors)

  3. Evaluation of neutron shielding properties of lead glass using bubble detector

    International Nuclear Information System (INIS)

    Viswanathan, S.; Vishwa Prasad, K.; Srinivasan, T.K.; Ponraju, D.

    1999-01-01

    Neutron shielding properties of lead glass had been studied using a 241 Am-Be neutron source. Indigenously developed bubble detector was used as neutron detector. Attenuation curves were determined experimentally for the lead glass under the conditions of broad beam geometry. Theoretical calculations were made using Monte Carlo code MCNP3. Measurements were made for polyethylene and concrete to serve as reference. The measured and calculated neutron removal cross sections of lead glass, polyethylene and concrete are reported in this paper. Good agreement is observed between the experimental results and theoretical calculations. (author)

  4. Evaluation of radiation shielding rate of lead aprons in nuclear medicine

    International Nuclear Information System (INIS)

    Han, Sang Hyun; Han, Beom Heui; Lee, Sang Ho; Hong, Dong Heui; Kim, Gi Jin

    2017-01-01

    Considering that the X-ray apron used in the department of radiology is also used in the department of nuclear medicine, the study aimed to analyze the shielding rate of the apron according to types of radioisotopes, thus γ ray energy, to investigate the protective effects. The radioisotopes used in the experiment were the top 5 nuclides in usage statistics "9"9"mTc, "1"8F, "1"3"1I, "1"2"3I, and "2"0"1Tl, and the aprons were lead equivalent 0.35 mmPb aprons currently under use in the department of nuclear medicine. As a result of experiments, average shielding rates of aprons were "9"9"mTc 31.59%, "2"0"1Tl 68.42%, and "1"2"3I 76.63%. When using an apron, the shielding rate of "1"3'1I actually resulted in average dose rate increase of 33.72%, and "1"8F showed an average shielding rate of –0.315%, showing there was almost no shielding effect. As a result, the radioisotopes with higher shielding rate of apron was in the descending order of "1"2"3I, "2"0"1Tl, "9"9"mTc, "1"8F, "1"3"1I. Currently, aprons used in the nuclear medicine laboratory are general X-ray aprons, and it is thought that it is not appropriate for nuclear medicine environment that utilizes γ rays. Therefore, development of nuclear medicine exclusive aprons suitable for the characteristics of radioisotopes is required in consideration of effective radiation protection and work efficiency of radiation workers

  5. The use of steel and lead shieldings in radiotherapy rooms and its comparison with respect to neutrons doses at patients

    International Nuclear Information System (INIS)

    Silva, M.G.; Rebello, W.F.; Andrade, E.R.; Medeiros, M.P.C.; Mendes, R.M.S.; Braga, K.L.; Gomes, R.G.; Santos, R.F.G.

    2015-01-01

    The NCRP Report No. 151, Structural Shielding Design and Evaluation for Megavoltage X- and Gamma-Ray Radiotherapy Facilities, considers, in shielding calculations for radiotherapy rooms, the use of lead and/or steel to be applied on bunker walls. The NCRP Report calculations were performed foreseeing a better protection of people outside the radiotherapy room. However, contribution of lead and steel to patient dose should be taken into account for radioprotection purposes. This work presents calculations performed by MCNPX code in analyzing the Ambient Dose Equivalent due to neutron, H*(10) n , within a radiotherapy room, in the patients area, considering the use of additional shielding of 1 TVL of lead or 1 TVL of steel, positioned at the inner faces of walls and ceiling of a bunker. The head of the linear accelerator Varian 2100/2300 C/D was modeled working at 18MeV, with 5x5cm 2 , 10x10cm 2 , 20x20cm 2 , 30x30cm 2 and 40x40cm 2 openings for jaws and MLC and operating in eight gantry's angles. This study shows that the use of lead generates an average value of H*(10) n at patients area, 8.02% higher than the expected when using steel. Further studies should be performed based on experimental data for comparison with those from MCNPX simulation.

  6. Dose estimates in a loss of lead shielding truck accident.

    Energy Technology Data Exchange (ETDEWEB)

    Dennis, Matthew L.; Osborn, Douglas M.; Weiner, Ruth F.; Heames, Terence John (Alion Science & Technology Albuquerque, NM)

    2009-08-01

    The radiological transportation risk & consequence program, RADTRAN, has recently added an updated loss of lead shielding (LOS) model to it most recent version, RADTRAN 6.0. The LOS model was used to determine dose estimates to first-responders during a spent nuclear fuel transportation accident. Results varied according to the following: type of accident scenario, percent of lead slump, distance to shipment, and time spent in the area. This document presents a method of creating dose estimates for first-responders using RADTRAN with potential accident scenarios. This may be of particular interest in the event of high speed accidents or fires involving cask punctures.

  7. Structural shielding of medical X-ray rooms for diagnostic installations

    International Nuclear Information System (INIS)

    Rabitsch, H.

    1979-06-01

    In Part I (RIG 8), the various design procedures for shielding against X-rays are discussed and compared. In particular, this comparison is carried out between the shielding obtained conforming to the Austrian Regulations for Radiation Protection and that obtained from the DIN-standard DIN 6812; this latter includes the various operating conditions of diagnostic installations up to 150 kV. Several examples for particular structural shielding components in medical radiation rooms are given. (author)

  8. Studying the shielding properties of lead glass composites using neutrons and gamma rays

    International Nuclear Information System (INIS)

    Osman, A.M.; El-Sarraf, M.A.; Abdel-Monem, A.M.; El-Sayed Abdo, A.

    2015-01-01

    Highlights: • Samples of sodalime silica glass loaded with different ratios of PbO were prepared. • Leaded glass composites were investigated for radiation shielding. • Experimental and theoretical attenuation parameters were studied. • Experimental and theoretical (MCNP5) results were in good agreement. - Abstract: The present work deals with the shielding properties of lead glass composites to find out its integrity for practical shielding applications and radiological safety. Composites of different lead oxide ratios (x = 0, 5, 10, 15 and 25 wt.%) have been prepared by the Nasser Glass and Crystal Company (Egypt). Attenuation measurements have been carried out using a collimated emitted beam from a fission 252 Cf (100 μg) neutron source, and the neutron–gamma spectrometer with stilbene scintillator. The pulse shape discriminating (P.S.D.) technique based on the zero cross-over method was used to discriminate between neutron and gamma-ray pulses. Thermal neutron fluxes were measured using the BF3 detector and thermal neutron detection system. The attenuation relations were used to evaluate fast neutron macroscopic effective removal cross-section Σ R-Meas (cm −1 ), gamma rays total attenuation coefficient μ (cm −1 ) and thermal neutron macroscopic cross-section Σ Meas (cm −1 ). Theoretical calculations have been achieved using MCNP5 code to calculate the same two parameters. Also, MERCSF-N program was used to calculate fast neutron macroscopic removal cross-section Σ R-MER (cm −1 ). Measured and MCNP5 calculated results have been compared and were found to be in reasonable agreement

  9. Fabrication of Radiation Shielding Glasses Based on Lead-free High Refractive Index Glasses Prepared from Local Sand

    International Nuclear Information System (INIS)

    Dararutana, Pisutti; Dutchaneepet, Jirapan; Sirikulrat, Narin

    2007-08-01

    Full text: Lead glasses that show high refractive index are the best know and most popular for radiation shielding. Due to harmful effects of lead and considering the health as well as the environmental issues, lead-free glasses were developed. In this work, content of Chumphon sand was fixed at 40 % (by weight) as a main composition but concentrations of BaCO3 were varied from 6 to 30 % (by weight). It was found that the absorption coefficient of the glass samples containing 30 % BaCO3 was 0.233 cm-1 for Ba-133. The density was also measured. It can be concluded that the prepared lead free glasses offered adequate shielding to gamma radiation in comparison with the lead ones. These glasses were one of the environmental friendly materials

  10. Simulation of photon attenuation coefficients for high effective shielding material Lead-Boron Polyethyene

    Science.gov (United States)

    Zhang, L.; Jia, M. C.; Gong, J. J.; Xia, W. M.

    2017-12-01

    The mass attenuation coefficient of various Lead-Boron Polyethylene samples which can be used as the photon shielding materials in marine reactor, have been simulated using the MCNP-5 code, and compared with the theoretical values at the photon energy range 0.001MeV—20MeV. A good agreement has been observed. The variations of mass attenuation coefficient, linear attenuation coefficient and mean free path with photon energy between 0.001MeV to 100MeV have been plotted. The result shows that all the coefficients strongly depends on the photon energy, material atomic composition and density. The dose transmission factors for source Cesium-137 and Cobalt-60 have been worked out and their variations with the thickness of various sample materials have also been plotted. The variations show that with the increase of materials thickness the dose transmission factors decrease continuously. The results of this paper can provide some reference for the use of the high effective shielding material Lead-Boron Polyethyene.

  11. Shielding effect of clinical x-ray protector and lead glass against annihilation radiation and gamma rays of 99mTc

    International Nuclear Information System (INIS)

    Fukuda, Atsushi; Takahashi, Masaaki; Kitabayashi, Keitarou; Koshida, Kichiro; Matsubara, Kousuke; Noto, Kimiya; Nakagawa, Hiroto; Kawabata, Chikako

    2004-01-01

    Various pharmaceutical companies in Japan are making radioactive drugs available for positron emission tomography (PET) in hospitals without a cyclotron. With the distribution of these drugs to hospitals, medical check-ups and examinations using PET are expected to increase. However, the safety guidelines for radiation in the new deployment of PET have not been adequately improved. Therefore, we measured the shielding effect of a clinical X-ray protector and lead glass against annihilation radiation and gamma rays of 99m Tc. We then calculated the shielding effect of a 0.25 mm lead protector, 1 mm lead, and lead glass using the EGS4 (Electron Gamma Shower Version 4) code. The shielding effects of 22-mm lead glass against annihilation radiation and gamma rays of 99m Tc were approximately 31.5% and 93.3%, respectively. The clinical X-ray protector against annihilation radiation approximately doubled the skin-absorbed dose. (author)

  12. [Shielding effect of clinical X-ray protector and lead glass against annihilation radiation and gamma rays of 99mTc].

    Science.gov (United States)

    Fukuda, Atsushi; Koshida, Kichiro; Yamaguchi, Ichiro; Takahashi, Masaaki; Kitabayashi, Keitarou; Matsubara, Kousuke; Noto, Kimiya; Kawabata, Chikako; Nakagawa, Hiroto

    2004-12-01

    Various pharmaceutical companies in Japan are making radioactive drugs available for positron emission tomography (PET) in hospitals without a cyclotron. With the distribution of these drugs to hospitals, medical check-ups and examinations using PET are expected to increase. However, the safety guidelines for radiation in the new deployment of PET have not been adequately improved. Therefore, we measured the shielding effect of a clinical X-ray protector and lead glass against annihilation radiation and gamma rays of (99m)Tc. We then calculated the shielding effect of a 0.25 mm lead protector, 1 mm lead, and lead glass using the EGS4 (Electron Gamma Shower Version 4) code. The shielding effects of 22-mm lead glass against annihilation radiation and gamma rays of (99m)Tc were approximately 31.5% and 93.3%, respectively. The clinical X-ray protector against annihilation radiation approximately doubled the skin-absorbed dose.

  13. Contaminant deposition building shielding factors for US residential structures.

    Science.gov (United States)

    Dickson, Elijah; Hamby, David; Eckerman, Keith

    2017-10-10

    This paper presents validated building shielding factors designed for contemporary US housing-stock under an idealized, yet realistic, exposure scenario from contaminant deposition on the roof and surrounding surfaces. The building shielding factors are intended for use in emergency planning and level three probabilistic risk assessments for a variety of postulated radiological events in which a realistic assessment is necessary to better understand the potential risks for accident mitigation and emergency response planning. Factors are calculated from detailed computational housing-units models using the general-purpose Monte Carlo N-Particle computational code, MCNP5, and are benchmarked from a series of narrow- and broad-beam measurements analyzing the shielding effectiveness of ten common general-purpose construction materials and ten shielding models representing the primary weather barriers (walls and roofs) of likely US housing-stock. Each model was designed to scale based on common residential construction practices and include, to the extent practical, all structurally significant components important for shielding against ionizing radiation. Calculations were performed for floor-specific locations from contaminant deposition on the roof and surrounding ground as well as for computing a weighted-average representative building shielding factor for single- and multi-story detached homes, both with and without basement as well for single-wide manufactured housing-unit. © 2017 IOP Publishing Ltd.

  14. Contaminant deposition building shielding factors for US residential structures

    International Nuclear Information System (INIS)

    Dickson, E D; Hamby, D M; Eckerman, K F

    2015-01-01

    This paper presents validated building shielding factors designed for contemporary US housing-stock under an idealized, yet realistic, exposure scenario from contaminant deposition on the roof and surrounding surfaces. The building shielding factors are intended for use in emergency planning and level three probabilistic risk assessments for a variety of postulated radiological events in which a realistic assessment is necessary to better understand the potential risks for accident mitigation and emergency response planning. Factors are calculated from detailed computational housing-units models using the general-purpose Monte Carlo N-Particle computational code, MCNP5, and are benchmarked from a series of narrow- and broad-beam measurements analyzing the shielding effectiveness of ten common general-purpose construction materials and ten shielding models representing the primary weather barriers (walls and roofs) of likely US housing-stock. Each model was designed to scale based on common residential construction practices and include, to the extent practical, all structurally significant components important for shielding against ionizing radiation. Calculations were performed for floor-specific locations from contaminant deposition on the roof and surrounding ground as well as for computing a weighted-average representative building shielding factor for single- and multi-story detached homes, both with and without basement as well for single-wide manufactured housing-unit. (paper)

  15. Cloud immersion building shielding factors for US residential structures

    International Nuclear Information System (INIS)

    Dickson, E D; Hamby, D M

    2014-01-01

    This paper presents validated building shielding factors designed for contemporary US housing-stock under an idealized, yet realistic, exposure scenario within a semi-infinite cloud of radioactive material. The building shielding factors are intended for use in emergency planning and level three probabilistic risk assessments for a variety of postulated radiological events in which a realistic assessment is necessary to better understand the potential risks for accident mitigation and emergency response planning. Factors are calculated from detailed computational housing-units models using the general-purpose Monte Carlo N-Particle computational code, MCNP5, and are benchmarked from a series of narrow- and broad-beam measurements analyzing the shielding effectiveness of ten common general-purpose construction materials and ten shielding models representing the primary weather barriers (walls and roofs) of likely US housing-stock. Each model was designed to scale based on common residential construction practices and include, to the extent practical, all structurally significant components important for shielding against ionizing radiation. Calculations were performed for floor-specific locations as well as for computing a weighted-average representative building shielding factor for single- and multi-story detached homes, both with and without basement, as well for single-wide manufactured housing-units. (paper)

  16. Penetration portion shielding structure

    International Nuclear Information System (INIS)

    Hayashi, Katsumi; Narita, Hitoshi; Handa, Hiroyuki; Takeuchi, Jun; Tozuka, Fumio.

    1994-01-01

    Openings of a plurality of shieldings for penetration members are aligned to each other, and penetration members are inserted from the openings. Then, the openings of the plurality of shielding members are slightly displaced with each other to make the penetration portions into a helical configuration, so that leakage of radiation is reduced. Upon removal of the members, reverse operation is conducted. When a flowable shielding material is used, the penetration portions are constituted with two plates having previously formed openings and pipes for connecting the openings with each other and a vessel covering the entire of them. After passing the penetration members such as a cable, the relative position of the two plates is changed by twisting, to form a helical configuration which reduces radiation leakage. Since they are bent into the helical configuration, shielding performance is extremely improved compared with a case that radiation leakage is caused from an opening of a straight pipe. In addition, since they can be returned to straight pipes, attachment, detachment and maintenance can be conducted easily. (N.H.)

  17. Thermal Degradation of Lead Monoxide Filled Polymer Composite Radiation Shields

    International Nuclear Information System (INIS)

    Harish, V.; Nagaiah, N.

    2011-01-01

    Lead monoxide filled Isophthalate resin particulate polymer composites were prepared with different filler concentrations and investigated for physical, thermal, mechanical and gamma radiation shielding characteristics. This paper discusses about the thermo gravimetric analysis of the composites done to understand their thermal properties especially the effect of filler concentration on the thermal stability and degradation rate of composites. Pristine polymer exhibits single stage degradation whereas filled composites exhibit two stage degradation processes. Further, the IDT values as well as degradation rates decrease with the increased filler content in the composite.

  18. Shielding practice

    International Nuclear Information System (INIS)

    Sauermann, P.F.

    1985-08-01

    The basis of shielding practice against external irradiation is shown in a simple way. For most sources of radiation (point sources) occurring in shielding practice, the basic data are given, mainly in the form of tables, which are required to solve the shielding problems. The application of these data is explained and discussed using practical examples. Thickness of shielding panes of glove boxes for α and β radiation; shielding of sealed γ-radiography sources; shielding of a Co-60 radiation source, and of the manipulator panels for hot cells; damping factors for γ radiation and neutrons; shielding of fast and thermal neutrons, and of bremsstrahlung (X-ray tubes, Kr-85 pressure gas cylinders, 42 MeV betatrons, 20 MeV linacs); two-fold shielding (lead glass windows for hot cells, 14 MeV neutron generators); shielding against scattered radiation. (orig./HP) [de

  19. A comparison of dose savings of lead and lightweight aprons for shielding of 99m-Technetium radiation

    International Nuclear Information System (INIS)

    Warren-Forward, H.; Cardew, P.; Smith, B.; Clack, L.; McWhirter, K.; Johnson, S.; Wessel, K.

    2007-01-01

    Nuclear medicine technologists (NMTs) have the highest effective doses of radiation among medical workers. With increase in the use of lightweight materials in diagnostic radiography, the aim was to compare the effectiveness of lead and lightweight aprons in shielding from 99m-Technetium ( 99m Tc) gamma rays. The doses received from a scattering phantom to the entrance, 9 cm depth and exit of a phantom were measured with LiF:Mg, Cu, P thermoluminescent dosemeters (TLDs). Doses and spectra were assessed without no shielding, with 0.5-mm lead and lightweight aprons. The lead and lightweight aprons decreased entrance surface doses by 76 and 59%, respectively. The spectral analysis showed that the lightweight apron provided better dose reduction at energies 99m Tc labelled radiopharmaceutical. (authors)

  20. Comparative study of lead borate and bismuth lead borate glass systems as gamma-radiation shielding materials

    International Nuclear Information System (INIS)

    Singh, Narveer; Singh, Kanwar Jit; Singh, Kulwant; Singh, Harvinder

    2004-01-01

    Gamma-ray mass attenuation coefficients have been measured experimentally and calculated theoretically for PbO-B 2 O 3 and Bi 2 O 3 -PbO-B 2 O 3 glass systems using narrow beam transmission method. These values have been used to calculate half value layer (HVL) parameter. These parameters have also been calculated theoretically for some standard radiation shielding concretes at same energies. Effect of replacing lead by bismuth has been analyzed in terms of density, molar volume and mass attenuation coefficient

  1. Dynamic Analysis of AP1000 Shield Building Considering Fluid and Structure Interaction Effects

    Directory of Open Access Journals (Sweden)

    Qiang Xu

    2016-02-01

    Full Text Available The shield building of AP1000 was designed to protect the steel containment vessel of the nuclear reactor. Therefore, the safety and integrity must be ensured during the plant life in any conditions such as an earthquake. The aim of this paper is to study the effect of water in the water tank on the response of the AP1000 shield building when subjected to three-dimensional seismic ground acceleration. The smoothed particle hydrodynamics method (SPH and finite element method (FEM coupling method is used to numerically simulate the fluid and structure interaction (FSI between water in the water tank and the AP1000 shield building. Then the grid convergence of FEM and SPH for the AP1000 shield building is analyzed. Next the modal analysis of the AP1000 shield building with various water levels (WLs in the water tank is taken. Meanwhile, the pressure due to sloshing and oscillation of the water in the gravity drain water tank is studied. The influences of the height of water in the water tank on the time history of acceleration of the AP1000 shield building are discussed, as well as the distributions of amplification, acceleration, displacement, and stresses of the AP1000 shield building. Research on the relationship between the WLs in the water tank and the response spectrums of the structure are also taken. The results show that the high WL in the water tank can limit the vibration of the AP1000 shield building and can more efficiently dissipate the kinetic energy of the AP1000 shield building by fluid-structure interaction.

  2. Shielded helix traveling wave cathode ray tube deflection structure

    Science.gov (United States)

    Norris, N.J.; Hudson, C.L.

    1992-12-15

    Various embodiments of a helical coil deflection structure of a CRT are described and illustrated which provide shielding between adjacent turns of the coil on either three or four sides of each turn in the coil. Threaded members formed with either male or female threads and having the same pitch as the deflection coil are utilized for shielding the deflection coil with each turn of the helical coil placed between adjacent threads which act to shield each coil turn from adjacent turns and to confine the field generated by the coil to prevent or inhibit cross-coupling between adjacent turns of the coil to thereby prevent generation of fast fields which might otherwise deflect the beam out of time synchronization with the electron beam pulse. 13 figs.

  3. SU-F-I-72: Evaluation of the Ancillary Lead Shielding for Optimizing Radiation Protection in the Interventional Radiology Department

    Energy Technology Data Exchange (ETDEWEB)

    Tonkopi, E; Lightfoot, C [Dalhousie University, Queen Elizabeth II Health Sciences Ctr, Halifax, NS (Canada); LeBlanc, E [Queen Elizabeth II Health Sciences Ctr, Halifax, NS (Canada)

    2016-06-15

    Purpose: The rising complexity of interventional fluoroscopic procedures has resulted in an increase of occupational radiation exposures in the interventional radiology (IR) department. This study assessed the impact of ancillary shielding on optimizing radiation protection for the IR staff. Methods: Scattered radiation measurements were performed in two IR suites equipped with Axiom Artis systems (Siemens Healthcare, Erlangen, Germany) installed in 2006 and 2010. Both rooms had suspended ceiling-mounted lead-acrylic shields of 75×60 cm (Mavig, Munich, Germany) with lead equivalency of 0.5 mm, and under-table drapes of 70×116 cm and 65×70 cm in the newer and the older room respectively. The larger skirt can be wrapped around the table’s corner and in addition the newer suite had two upper shields of 25×55 cm and 25×35 cm. The patient was simulated by 30 cm of acrylic, air kerma rate (AKR) was measured with the 180cc ionization chamber (AccuPro Radcal Corporation, Monrovia, CA, USA) at different positions. The ancillary shields, x-ray tube, image detector, and table height were adjusted by the IR radiologist to simulate various clinical setups. The same exposure parameters were used for all acquisitions. AKR measurements were made at different positions relative to the operator. Results: The AKR measurements demonstrated 91–99% x-ray attenuation by the drapes in both suites. The smaller size of the under-table skirt and absence of the side-drapes in the older room resulted in a 20–50 fold increase of scattered radiation to the operator. The mobile suspended lead-acrylic shield reduced AKR by 90–94% measured at 150–170 cm height. The recommendations were made to replace the smaller under-table skirt and to use the ceiling-mounted shields for all IR procedures. Conclusion: The ancillary shielding may significantly affect radiation exposure to the IR staff. The use of suspended ceiling-mounted shields is especially important for reduction of

  4. Multi-functional layered structure having structural and radiation shielding attributes

    Science.gov (United States)

    Kaul, Raj K. (Inventor); Barghouty, Abdulnasser Fakhri (Inventor); Penn, Benjamin G. (Inventor); Hulcher, Anthony Bruce (Inventor)

    2010-01-01

    A cosmic and solar radiation shielding structure that also has structural attributes is comprised of three layers. The first layer is 30-42 percent by volume of ultra-high molecular weight (UHMW) polyethylene fibers, 18-30 percent by volume of graphite fibers, and a remaining percent by volume of an epoxy resin matrix. The second layer is approximately 68 percent by volume of UHMW polyethylene fibers and a remaining percent by volume of a polyethylene matrix. The third layer is a ceramic material.

  5. Comparison of eye shields in radiotherapeutic beams

    International Nuclear Information System (INIS)

    Currie, B.E.; Wellington Hospital, Wellington; Johnson, A.D.

    2004-01-01

    Full text: Both MeV electrons and kV photons are used in the treatment of superficial cancers. The advantages and disadvantages for each of these modalities have been widely reported in the literature (See for example [1-2]). Of particular note in the literature is the use of lead and tungsten eye shields to protect ocular structures during radiotherapy. An investigation addressing issues raised in the literature that are relevant to the Wellington Cancer Centre method of treatment of lesions near the eye shall be summarised. Various small sized fields were irradiated to determine depth dose and profile curves in a water phantom shielded by various commercially available eye shields. Transmission factors relevant to critical ocular structures and particle distribution theories are used to further elucidate the comparison between the use of MeV electrons and kV photons in the treatment of superficial cancers. Superficial X-rays from a Pantak Therapax unit SXT 150 model of HVL 4.90mm Al were used for the lead eye shield measurements and electrons from a Varian Clinac 2100C nominal energies 6MeV and 9MeV (R p 3.00cm and 4.34cm respectively) were used for the tungsten eye shield measurements. For the photon measurements circular applicators of 3cm, 4cm and 5cm diameter were used and for the electrons standard 6x6cm and 10x 10cm applicators were used, with no custom inserts. A Scanditronix RFA-300 water phantom and Scanditronix RFAplus version 5.3 software application were used to collect and collate all data. The eye shields were the Radiation Products Design Inc. medium lead eye shield (item 934-014) and the MED-TEC tungsten eye shields MT-T-45 M and MT-T-45 S. It is demonstrated that electron fields have appreciably greater scatter into the area directly under the eye shields than the photon fields. Similarly at the region of d max for the electron fields the relative dose is appreciably greater than the photon fields at similar depth. The relative merits for

  6. Radiation shielding in dental radiography

    International Nuclear Information System (INIS)

    Stenstroem, B.; Rehnmark-Larsson, S.; Julin, P.; Richter, S.

    1983-01-01

    The protective effect in the thyroid region from different types of radiation shieldings at intraoral radiography has been studied as well as the reduction of the absorbed dose to the sternal and the gonadal regions. The shieldings tested were five different types of leaded aprons, of which three had an attached leaded collar and the other two were used in combination with separate soft leaded collars. Furthermore one of the soft leaded collars and an unflexible horizontal leaded shield were tested separately. Two dental x-ray machines of 60 and 65 kVp with rectangular and circular tube collimators were used. The exposure time corresponded to speed group E film. The absorbed doses were measured with two ionization chambers. No significant difference in the protective effect in the thyroid gland could be found between the different types of radiation shieldings. There was a dose reduction by approximately a factor of 2 to the thyroid region down to 0.08 mGy per full survey using parallelling technique, and below 0.001 mGy per single bitewing exposure. The shieldings reduced the thyroid dose using bisecting-angle technique by a factor of 5 down to 0.15 mGy per full survey (20 exposures). In the sternal region the combinations of apron and collar reduced the absorbed dose from a full survey to below 2 μGy compared with 18 μGy (parallelling) and 31 μGy (biscting-angle) without any shielding. With the horizontal leaded shield a reduction by a factor of 6 was obtained but no significant sternal dose reduction could be detected from the soft collar alone. The gonadal dose could be reduced by a factor of 10 with the horizontal leaded shield, parallelling technique and circular collimator. Using leaded aprons the gonadal dose was approximately one per cent of the dose without any shielding, i.e. below 0.01 μGy per single intraoral exposure. (Authors)

  7. Radiation shielding method for pipes, etc

    International Nuclear Information System (INIS)

    Nagao, Tetsuya; Takahashi, Shuichi.

    1988-01-01

    Purpose: To constitute shielding walls of a dense structure around pipes and enable to reduce the wall thickness thereof upon periodical inspection, etc. for nuclear power plants. Constitution: For those portions of pipes requring shieldings, cylindrical vessels surrounding the portions are disposed and connected to a mercury supply system, a mercury discharge system and a freezing system for solidifying mercury. After charging mercury in a tank by way of a supply hose to the cylindrical vessels, the temperature of the mercury is lowered below the freezing point thereof to solidify the mercury while circulating cooling medium, to thereby form dense cylindrical radioactive-ray shielding walls. The specific gravity of mercury is greater than that of lead and, accordingly, the thickness of the shielding walls can be reduced as compared with the conventional wall thickness of the entire laminates. (Takahashi, M.)

  8. Contribution of 210Pb bremsstrahlung to the background of lead shielded gamma spectrometers

    International Nuclear Information System (INIS)

    Mrda, D.; Bikit, I.; Veskovic, M.; Forkapic, S.

    2007-01-01

    Lead, which is often used as a shielding material, contains 210 Pb (T 1/2 =22.3 y). The 46.54 keV γ-intensity of 210 Pb can be easily reduced by an inner lining, but the bremsstrahlung caused by the β-decay of its daughter, 210 Bi, with a maximal electron energy of 1.16 MeV, will contribute to the gamma detector background. The spectrum of this bremsstrahlung is calculated by numerically fitting the β-spectrum and integrating the Koch-Motz formula. The absorption of the bremsstrahlung in the lead and detection efficiencies for the HPGe detector are calculated by the effective solid angle algorithm, using corrections for the photopeak/Compton ratio of cross-sections in Ge. By comparison with the measured background spectrum, it is shown that, for the lead with 25 Bq/kg of 210 Pb up to 500 keV of gamma spectrum, the bremsstrahlung contribution to the background is about 20% for our surface-based detector system. Also, we compared our calculations with a Monte Carlo simulation of another detector system with a shield containing 1 Bq/kg of 210 Pb and found that our analytical method gives a value of roughly two times higher than the Monte Carlo one for the total bremsstrahlung contribution. The quality of the analytical semi-empirical method is proved by the reasonable agreement with the experimental results published

  9. Calculation of Buildup Factor for Gamma-ray Exposure in Two Layered Shields Made of Water and Lead

    International Nuclear Information System (INIS)

    Al-Saadi, A.H.

    2012-01-01

    The buildup factor for gamma ray exposure is most useful in calculations for biological protective shields.The buildup factors for gamma ray exposure were calculated in tow layered shields consist of water-lead and lead-water up to optical Thickness 20 mean free path (mfp) at gamma ray energies 1, 2 and 6MeV by using kalos's formula.The program has been designed to work at any atomic number of the attenuating medium, photon energy, slab thickness and and the arrangement of materials.The results obtained in this search leading to the buildup factor for gamma ray exposure at energies (1and2MeV) in lead-water were higher than the reverse case,while at energy 6 MeV the effect was opposite.The calculated data were parameterized by an empirical formula as a function of optical thickness of tow materials.The results obtained were in reasonable agreement with a previous work

  10. Orthogonally interdigitated shielded serpentine travelling wave cathode ray tube deflection structure

    Science.gov (United States)

    Hagen, E.C.; Hudson, C.L.

    1995-07-25

    A new deflection structure which deflects a beam of charged particles, such as an electron beam, includes a serpentine set for transmitting a deflection field, and a shielding frame for housing the serpentine set. The serpentine set includes a vertical serpentine deflection element and a horizontal serpentine deflection element. These deflection elements are identical, and are interdigitatedly and orthogonally disposed relative to each other, for forming a central transmission passage, through which the electron beam passes, and is deflected by the deflection field, so as to minimize drift space signal distortion. The shielding frame includes a plurality of ground blocks, and forms an internal serpentine trough within these ground blocks, for housing the serpentine set. The deflection structure further includes a plurality of feedthrough connectors which are inserted through the shielding frame, and which are electrically connected to the serpentine set. 10 figs.

  11. Lead shielded cells for the spectrographic analysis of radioisotope solutions

    International Nuclear Information System (INIS)

    Roca, M.; Capdevila, C.; Cruz, F. de la

    1967-01-01

    Two lead shielded cells for the spectrochemical analysis of radioisotope samples are described. One of them is devoted to the evaporation of samples before excitation and the other one contains a suitable spectrographic excitation stand for the copper spark technique. A special device makes it possible the easy displacement of the excitation cell on wheels and rails for its accurate and reproducible position as well as its replacement by a glove box for plutonium analysis. In order to guarantee safety the room in which the spectrograph and the source are set up in separated from the active laboratory by a wall with a suitable window. (Author) 1 refs

  12. Method of constructing shielding wall

    International Nuclear Information System (INIS)

    Nagao, Tetsuya.

    1990-01-01

    For instance, surfaces of lead particles each formed into a sphere of about 0.5 to 0.3 mm grain size are coated with a coating material of a synthetic resin comprising a polymeric material such as teflon. Subsequently, the floated lead particle are kneaded with concrete materials and then poured into a molding die by way of a hose. After coagulation, the molding die is removed to complete shielding walls in which lead particles are scattered substantially at an equal distance. In this way, since the lead particles are mixed into the shielding walls, shielding effects can be improved by so much as the lead particles are mixed, thereby enabling to reduce the thickness of the shielding walls. Further, since the lead particles are coated with the coating material, the lead particles are insulated from the concrete materials, thereby enabling to prevent the corrosion of the lead particles. Furthermore, since the lead particles and the concrete materials can be transported with ease, operation labors can be reduced. (T.M.)

  13. Shielding Design and Radiation Shielding Evaluation for LSDS System Facility

    International Nuclear Information System (INIS)

    Kim, Younggook; Kim, Jeongdong; Lee, Yongdeok

    2015-01-01

    As the system characteristics, the target in the spectrometer emits approximately 1012 neutrons/s. To efficiently shield the neutron, the shielding door designs are proposed for the LSDS system through a comparison of the direct shield and maze designs. Hence, to guarantee the radiation safety for the facility, the door design is a compulsory course of the development of the LSDS system. To improve the shielding rates, 250x250 covering structure was added as a subsidiary around the spectrometer. In this study, the evaluations of the suggested shielding designs were conducted using MCNP code. The suggested door design and covering structures can shield the neutron efficiently, thus all evaluations of all conditions are satisfied within the public dose limits. From the Monte Carlo code simulation, Resin(Indoor type) and Tungsten(Outdoor type) were selected as the shielding door materials. From a comparative evaluation of the door thickness, In and Out door thickness was selected 50 cm

  14. Piping structural design for the ITER thermal shield manifold

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Chang Hyun, E-mail: chnoh@nfri.re.kr [ITER Korea, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Chung, Wooho, E-mail: whchung@nfri.re.kr [ITER Korea, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Nam, Kwanwoo; Kang, Kyoung-O. [ITER Korea, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Bae, Jing Do; Cha, Jong Kook [Korea Marine Equipment Research Institute, Busan 606-806 (Korea, Republic of); Kim, Kyoung-Kyu [Mecha T& S, Jinju-si 660-843 (Korea, Republic of); Hamlyn-Harris, Craig; Hicks, Robby; Her, Namil; Jun, Chang-Hoon [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France)

    2015-10-15

    Highlights: • We finalized piping design of ITER thermal shield manifold for procurement. • Support span is determined by stress and deflection limitation. • SQP, which is design optimization method, is used for the pipe design. • Benchmark analysis is performed to verify the analysis software. • Pipe design is verified by structural analyses. - Abstract: The thermal shield (TS) provides the thermal barrier in the ITER tokamak to minimize heat load transferred by thermal radiation from the hot components to the superconducting magnets operating at 4.2 K. The TS is actively cooled by 80 K pressurized helium gas which flows from the cold valve box to the cooling tubes on the TS panels via manifold piping. This paper describes the manifold piping design and analysis for the ITER thermal shield. First, maximum allowable span for the manifold support is calculated based on the simple beam theory. In order to accommodate the thermal contraction in the manifold feeder, a contraction loop is designed and applied. Sequential Quadratic Programming (SQP) method is used to determine the optimized dimensions of the contraction loop to ensure adequate flexibility of manifold pipe. Global structural behavior of the manifold is investigated when the thermal movement of the redundant (un-cooled) pipe is large.

  15. Evaluation of the effectiveness of the lead aprons and thyroid shields worn by cardiologists in angiography departments of two main general hospitals in Mashhad, Iran

    International Nuclear Information System (INIS)

    Bahreyni Toossi, M.T.; Zare, H.; Bayani, Sh.; Esmaili, S.

    2008-01-01

    In recent years coronary artery angiography and angioplasty procedures have become very popular. Consequently radiation protection of the cardiologists, their assistants and technicians working in the vicinity of the x-ray tube is essential. Although in recent years in developed countries, high dose x-ray examinations such as coronary angiography have attracted the attention of health physicists but in developing countries it may take some years before it would receive any attention. In Iran generally film badge is the most common personal radiation monitoring device used for this purpose; it is placed beneath the lead apron. The shielding effect of different lead aprons and thyroid shields have been evaluated. TL dosimeters, suitably calibrated, were placed over and under lead shields corresponding to the thyroid and gonad positions of the personnel. 223 angiography examinations by femoral route were included in this work. Four types of aprons and three types of thyroid shields were examined. They were different in shape and lead equivalent thickness. Our results have revealed that apron with 0.35 mmPb, one piece and front closed has maximum shielding effect. Also thyroid shield with 0.5 mmPb and very large edge provide a better protection against radiation than other types. (author)

  16. A new design of a lead-acrylic shield for staff dose reduction in radial and femoral access coronary catheterization

    Energy Technology Data Exchange (ETDEWEB)

    Eder, H. [Deptartment of Radiation Protection (Germany); Seidenbusch, M.C.; Treitl, M. [Muenchen Univ. Clinical Center (Germany). Inst. for Clinical Radiology; Gilligan, P. [Mater Private Hospital, Dublin (Ireland). Medical Physics

    2015-10-15

    Today's standard radiation protection during coronary angiography and percutaneous coronary interventions is the combined use of lead acrylic shields and table-mounted lower body protection. Ambient dose measurements, however, have shown that these protection devices need improvement. Using an anthropomorphic physical phantom, various scenarios were investigated with respect to personnel exposure: (a) enlarging the shield (b) adding a flexible protective curtain to the bottom side of the shield, and (c) application of radioprotective patient drapes. For visualization of the dose reduction effect, Monte Carlo simulations were performed. The flexible curtain in contact with the patient's body reduces the ambient dose rate at the operator's position by up to (87.5 % ± 7.1) compared to the situation with the bare shield. The use of both the flexible curtain and the patient drape reduces the ambient dose rate by up to (90.8 % ± 7). Similar results were achieved for the assisting personnel when they were positioned next to the operator. In addition, the enlarged shield provides better protection of the head region of tall operators. Adding a flexible protective curtain to the bottom side of the shield can protect operators from high doses, especially for body parts which are not protected by lead aprons, e.g. head, and eye lenses. This may be important with respect to lower dose limits for eye lenses in future. The protective effect in real-life working conditions is still being evaluated in an ongoing clinical study.

  17. Evaluation of radiation-shielding properties of the composite material

    International Nuclear Information System (INIS)

    Pavlenko, V.I.; Chekashina, N.I.; Yastrebinskij, R.N.; Sokolenko, I.V.; Noskov, A.V.

    2016-01-01

    The paper presents the evaluation of radiation-shielding properties of composite materials with respect to gamma-radiation. As a binder for the synthesis of radiation-shielding composites we used lead boronsilicate glass matrix. As filler we used nanotubular chrysotile filled with lead tungstate PbWO4. It is shown that all the developed composites have good physical-mechanical characteristics, such as compressive strength, thermal stability and can be used as structural materials. On the basis of theoretical calculation we described the graphs of the gamma-quanta linear attenuation coefficient depending on the emitted energy for all investigated composites. We founded high radiation-shielding properties of all the composites on the basis of theoretical and experimental data compared to materials conventionally used in the nuclear industry - iron, concrete, etc

  18. Thermal Analysis of a SHIELD Electromigration Test Structure

    Energy Technology Data Exchange (ETDEWEB)

    Benson, David A.; Bowman, Duane J.; Mitchell, Robert T.

    1999-05-01

    The steady state and transient thermal behavior of an electromigration test structure was analyzed. The test structure was a Sandia SHIELD (Self-stressing HIgh fregquency rELiability Device) electromigration test device manufactured by an outside vendor. This device has a high frequency oscillator circuit, a buffer circuit to isolate and drive the metal line to the tested (DUT), the DUT to be electromigrated itself, a metal resistance thermometry monitor, and a heater elment to temperature accelerate the electromigration effect.

  19. XRD, lead equivalent and UV-VIS properties study of Ce and Pr lead silicate glasses

    International Nuclear Information System (INIS)

    Alias, Nor Hayati; Abdullah, Wan Shafie Wan; Isa, Norriza Mohd; Isa, Muhammad Jamal Md; Zali, Nurazila Mat; Abdullah, Nuhaslinda Ee; Muhammad, Azali

    2014-01-01

    In this work, Cerium (Ce) and Praseodymium (Pr) containing lead silicate glasses were produced with 2 different molar ratios low (0.2 wt%) and high (0.4wt%). These types of glasses can satisfy the characteristics required for radiation shielding glasses and minimize the lead composition in glass. The radiation shielding properties of the synthesized glasses is explained in the form of lead equivalent study. The XRD diffraction and UV-VIS analysis were performed to observe the structural changes of the synthesis glasses at 1.5 Gy gamma radiation exposures

  20. Experimental shielding evaluation of the radiation protection provided by the structurally significant components of residential structures.

    Science.gov (United States)

    Dickson, E D; Hamby, D M

    2014-03-01

    The human health and environmental effects following a postulated accidental release of radioactive material to the environment have been a public and regulatory concern since the early development of nuclear technology. These postulated releases have been researched extensively to better understand the potential risks for accident mitigation and emergency planning purposes. The objective of this investigation is to provide an updated technical basis for contemporary building shielding factors for the US housing stock. Building shielding factors quantify the protection from ionising radiation provided by a certain building type. Much of the current data used to determine the quality of shielding around nuclear facilities and urban environments is based on simplistic point-kernel calculations for 1950s era suburbia and is no longer applicable to the densely populated urban environments realised today. To analyse a building's radiation shielding properties, the ideal approach would be to subject a variety of building types to various radioactive sources and measure the radiation levels in and around the building. While this is not entirely practicable, this research analyses the shielding effectiveness of ten structurally significant US housing-stock models (walls and roofs) important for shielding against ionising radiation. The experimental data are used to benchmark computational models to calculate the shielding effectiveness of various building configurations under investigation from two types of realistic environmental source terms. Various combinations of these ten shielding models can be used to develop full-scale computational housing-unit models for building shielding factor calculations representing 69.6 million housing units (61.3%) in the United States. Results produced in this investigation provide a comparison between theory and experiment behind building shielding factor methodology.

  1. Experimental shielding evaluation of the radiation protection provided by the structurally significant components of residential structures

    International Nuclear Information System (INIS)

    Dickson, E D; Hamby, D M

    2014-01-01

    The human health and environmental effects following a postulated accidental release of radioactive material to the environment have been a public and regulatory concern since the early development of nuclear technology. These postulated releases have been researched extensively to better understand the potential risks for accident mitigation and emergency planning purposes. The objective of this investigation is to provide an updated technical basis for contemporary building shielding factors for the US housing stock. Building shielding factors quantify the protection from ionising radiation provided by a certain building type. Much of the current data used to determine the quality of shielding around nuclear facilities and urban environments is based on simplistic point-kernel calculations for 1950s era suburbia and is no longer applicable to the densely populated urban environments realised today. To analyse a building’s radiation shielding properties, the ideal approach would be to subject a variety of building types to various radioactive sources and measure the radiation levels in and around the building. While this is not entirely practicable, this research analyses the shielding effectiveness of ten structurally significant US housing-stock models (walls and roofs) important for shielding against ionising radiation. The experimental data are used to benchmark computational models to calculate the shielding effectiveness of various building configurations under investigation from two types of realistic environmental source terms. Various combinations of these ten shielding models can be used to develop full-scale computational housing-unit models for building shielding factor calculations representing 69.6 million housing units (61.3%) in the United States. Results produced in this investigation provide a comparison between theory and experiment behind building shielding factor methodology. (paper)

  2. HPGe detector shielding adjustment

    International Nuclear Information System (INIS)

    Trnkova, L.; Rulik, P.

    2008-01-01

    Low-level background shielding of HPGe detectors is used mainly for environmental samples with very low content of radionuclides. National Radiation Protection Institute (SURO) in Prague is equipped with 14 HPGe detectors with relative efficiency up to 150%. The detectors are placed in a room built from materials with low content of natural radionuclides and equipped with a double isolation of the floor against radon. Detectors themselves are placed in lead or steel shielding. Steel shielding with one of these detectors with relative efficiency of 100% was chosen to be rebuilt to achieve lower minimum detectable activity (MDA). Additional lead and copper shielding was built up inside the original steel shielding to reduce the volume of the inner space and filled with nitrogen by means of evaporating liquid nitrogen. The additional lead and copper shielding, consequent reduction of the inner volume and supply of evaporated nitrogen, caused a decrease of the background count and accordingly MDA values as well. The effect of nitrogen evaporation on the net areas of peaks belonging to radon daughters is significant. The enhanced shielding adjustment has the biggest influence in low energy range, what can be seen in collected data. MDA values in energy range from 30 keV to 400 keV decreased to 0.65-0.85 of original value, in energy range from 400 keV to 2 MeV they fell to 0.70-0.97 of original value. (authors)

  3. Radiation Attenuation and Stability of ClearView Radiation Shielding TM-A Transparent Liquid High Radiation Shield.

    Science.gov (United States)

    Bakshi, Jayeesh

    2018-04-01

    Radiation exposure is a limiting factor to work in sensitive environments seen in nuclear power and test reactors, medical isotope production facilities, spent fuel handling, etc. The established choice for high radiation shielding is lead (Pb), which is toxic, heavy, and abidance by RoHS. Concrete, leaded (Pb) bricks are used as construction materials in nuclear facilities, vaults, and hot cells for radioisotope production. Existing transparent shielding such as leaded glass provides minimal shielding attenuation in radiotherapy procedures, which in some cases is not sufficient. To make working in radioactive environments more practicable while resolving the lead (Pb) issue, a transparent, lightweight, liquid, and lead-free high radiation shield-ClearView Radiation Shielding-(Radium Incorporated, 463 Dinwiddie Ave, Waynesboro, VA). was developed. This paper presents the motivation for developing ClearView, characterization of certain aspects of its use and performance, and its specific attenuation testing. Gamma attenuation testing was done using a 1.11 × 10 Bq Co source and ANSI/HPS-N 13.11 standard. Transparency with increasing thickness, time stability of liquid state, measurements of physical properties, and performance in freezing temperatures are reported. This paper also presents a comparison of ClearView with existing radiation shields. Excerpts from LaSalle nuclear power plant are included, giving additional validation. Results demonstrated and strengthened the expected performance of ClearView as a radiation shield. Due to the proprietary nature of the work, some information is withheld.

  4. Adjustable lead glass shielding device for use with a over-the-table x-ray tube

    International Nuclear Information System (INIS)

    Eubig, C.; Groves, B.M.; Davey, G.

    1978-01-01

    Sources of scattered radiation exposure to personnel from a ceiling-mounted x-ray tube were examined at the side of cardiac catheterization patients. A fully adjustable mounting for a lead glass shield was designed to afford maximum radiation protection to the attending physician's head and neck area, while minimizing interference with the procedure

  5. Adjustable lead glass shielding device for use with an over-the-table x-ray tube.

    Science.gov (United States)

    Eubig, C; Groves, B M; Davey, G

    1978-12-01

    Sources of scattered radiation exposure to personnel from a ceiling-mounted x-ray tube were examined at the side of cardiac catheterization patients. A fully adjustable mounting for a lead glass shield was designed to afford maximum radiation protection to the attending physician's head and neck area, while minimizing interference with the procedure.

  6. SU-F-I-71: Fetal Protection During Fluoroscopy: To Shield Or Not to Shield?

    International Nuclear Information System (INIS)

    Joshi, S; Vanderhoek, M

    2016-01-01

    Purpose: Lead aprons are routinely used to shield the fetus from radiation during fluoroscopically guided interventions (FGI) involving pregnant patients. When placed in the primary beam, lead aprons often reduce image quality and increase fluoroscopic radiation output, which can adversely affect fetal dose. The purpose of this work is to identify an effective and practical method to reduce fetal dose without affecting image quality. Methods: A pregnant patient equivalent abdominal phantom is set on the table along with an image quality test object (CIRS model 903) representing patient anatomy of interest. An ion chamber is positioned at the x-ray beam entrance to the phantom, which is used to estimate the relative fetal dose. For three protective methods, image quality and fetal dose measurements are compared to baseline (no protection):1. Lead apron shielding the entire abdomen; 2. Lead apron shielding part of the abdomen, including the fetus; 3. Narrow collimation such that fetus is excluded from the primary beam. Results: With lead shielding the entire abdomen, the dose is reduced by 80% relative to baseline along with a drastic deterioration of image quality. With lead shielding only the fetus, the dose is reduced by 65% along with complete preservation of image quality, since the image quality test object is not shielded. However, narrow collimation results in 90% dose reduction and a slight improvement of image quality relative to baseline. Conclusion: The use of narrow collimation to protect the fetus during FGI is a simple and highly effective method that simultaneously reduces fetal dose and maintains sufficient image quality. Lead aprons are not as effective at fetal dose reduction, and if placed improperly, they can severely degrade image quality. Future work aims to investigate a wider variety of fluoroscopy systems to confirm these results across many different system geometries.

  7. SU-F-I-71: Fetal Protection During Fluoroscopy: To Shield Or Not to Shield?

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, S; Vanderhoek, M [Henry Ford Health System, Detroit, MI (United States)

    2016-06-15

    Purpose: Lead aprons are routinely used to shield the fetus from radiation during fluoroscopically guided interventions (FGI) involving pregnant patients. When placed in the primary beam, lead aprons often reduce image quality and increase fluoroscopic radiation output, which can adversely affect fetal dose. The purpose of this work is to identify an effective and practical method to reduce fetal dose without affecting image quality. Methods: A pregnant patient equivalent abdominal phantom is set on the table along with an image quality test object (CIRS model 903) representing patient anatomy of interest. An ion chamber is positioned at the x-ray beam entrance to the phantom, which is used to estimate the relative fetal dose. For three protective methods, image quality and fetal dose measurements are compared to baseline (no protection):1. Lead apron shielding the entire abdomen; 2. Lead apron shielding part of the abdomen, including the fetus; 3. Narrow collimation such that fetus is excluded from the primary beam. Results: With lead shielding the entire abdomen, the dose is reduced by 80% relative to baseline along with a drastic deterioration of image quality. With lead shielding only the fetus, the dose is reduced by 65% along with complete preservation of image quality, since the image quality test object is not shielded. However, narrow collimation results in 90% dose reduction and a slight improvement of image quality relative to baseline. Conclusion: The use of narrow collimation to protect the fetus during FGI is a simple and highly effective method that simultaneously reduces fetal dose and maintains sufficient image quality. Lead aprons are not as effective at fetal dose reduction, and if placed improperly, they can severely degrade image quality. Future work aims to investigate a wider variety of fluoroscopy systems to confirm these results across many different system geometries.

  8. Shield design for next-generation, low-neutron-fluence, superconducting tokamaks

    International Nuclear Information System (INIS)

    Lee, V.D.; Gohar, Y.

    1985-01-01

    A shield design using stainless steel (SST), water, boron carbide, lead, and concrete materials was developed for the next-generation tokamak device with superconducting toroidal field (TF) coils and low neutron fluence. A device such as the Tokamak Fusion Core Experiment (TFCX) is representative of the tokamak design which could use this shield design. The unique feature of this reference design is that a majority of the bulk steel in the shield is in the form of spherical balls with two small, flat spots. The balls are purchased from ball-bearing manufacturers and are added as bulk shielding to the void areas of builtup, structural steel shells which form the torus cavity of the plasma chamber. This paper describes the design configuration of the shielding components

  9. Shield design for next-generation, low-neutron-fluence, superconducting tokamaks

    International Nuclear Information System (INIS)

    Lee, V.D.; Gohar, Y.

    1985-01-01

    A shield design using stainless steel (SST), water, boron carbide, lead, and concrete materials was developed for the next-generation tokamak device with superconducting toroidal field (TF) coils and low neutron fluence. A device such as the Tokamak Fusion Core Experiment (TFCX) is representative of the tokamak design which could use this shield design. The unique feature of this reference design is that a majority of the bulk steel in the shield is in the form of spherical balls with two small, flat spots. The balls are purchased from ball-bearing manufacturers and are added as bulk shielding to the void areas of built-up, structural steel shells which form the torus cavity of the plasma chamber. This paper describes the design configuration of the shielding components

  10. Mechanical shielded hot cell

    International Nuclear Information System (INIS)

    Higgy, H.R.; Abdel-Rassoul, A.A.

    1983-01-01

    A plan to erect a mechanical shielded hot cell in the process hall of the Radiochemical Laboratory at Inchas is described. The hot cell is designed for safe handling of spent fuel bundles, from the Inchas reactor, and for dismantling and cutting the fuel rods in preparation for subsequent treatment. The biological shielding allows for the safe handling of a total radioactivity level up to 10,000 MeV-Ci. The hot cell consists of an α-tight stainless-steel box, connected to a γ-shielded SAS, through an air-lock containing a movable carriage. The α-box is tightly connected with six dry-storage cavities for adequate storage of the spent fuel bundles. Both the α-box, with the dry-storage cavities, and the SAS are surrounded by 200-mm thick biological lead shielding. The α-box is equipped with two master-slave manipulators, a lead-glass window, a monorail crane and Padirac and Minirag systems. The SAS is equipped with a lead-glass window, tong manipulator, a shielded pit and a mechanism for the entry of the spent fuel bundle. The hot cell is served by adequate ventilation and monitoring systems. (author)

  11. PWR upper/lower internals shield

    Energy Technology Data Exchange (ETDEWEB)

    Homyk, W.A. [Indian Point Station, Buchanan, NY (United States)

    1995-03-01

    During refueling of a nuclear power plant, the reactor upper internals must be removed from the reactor vessel to permit transfer of the fuel. The upper internals are stored in the flooded reactor cavity. Refueling personnel working in containment at a number of nuclear stations typically receive radiation exposure from a portion of the highly contaminated upper intervals package which extends above the normal water level of the refueling pool. This same issue exists with reactor lower internals withdrawn for inservice inspection activities. One solution to this problem is to provide adequate shielding of the unimmersed portion. The use of lead sheets or blankets for shielding of the protruding components would be time consuming and require more effort for installation since the shielding mass would need to be transported to a support structure over the refueling pool. A preferable approach is to use the existing shielding mass of the refueling pool water. A method of shielding was devised which would use a vacuum pump to draw refueling pool water into an inverted canister suspended over the upper internals to provide shielding from the normally exposed components. During the Spring 1993 refueling of Indian Point 2 (IP2), a prototype shield device was demonstrated. This shield consists of a cylindrical tank open at the bottom that is suspended over the refueling pool with I-beams. The lower lip of the tank is two feet below normal pool level. After installation, the air width of the natural shielding provided by the existing pool water. This paper describes the design, development, testing and demonstration of the prototype device.

  12. Electromagnetically shielded building

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, T; Nakamura, M; Yabana, Y; Ishikawa, T; Nagata, K

    1992-04-21

    This invention relates to a building having an electromagnetic shield structure well-suited for application to an information network system utilizing electromagnetic waves, and more particularly to an electromagnetically shielded building for enhancing the electromagnetic shielding performance of an external wall. 6 figs.

  13. Electromagnetically shielded building

    International Nuclear Information System (INIS)

    Takahashi, T.; Nakamura, M.; Yabana, Y.; Ishikawa, T.; Nagata, K.

    1992-01-01

    This invention relates to a building having an electromagnetic shield structure well-suited for application to an information network system utilizing electromagnetic waves, and more particularly to an electromagnetically shielded building for enhancing the electromagnetic shielding performance of an external wall. 6 figs

  14. Structural Design and Thermal Analysis for Thermal Shields of the MICE Coupling Magnets

    International Nuclear Information System (INIS)

    Green, Michael A.; Pan, Heng; Liu, X.K.; Wang, Li; Wu, Hong; Chen, A.B.; Guo, X.L.

    2009-01-01

    A superconducting coupling magnet made from copper matrix NbTi conductors operating at 4 K will be used in the Muon Ionization Cooling Experiment (MICE) to produce up to 2.6 T on the magnet centerline to keep the muon beam within the thin RF cavity indows. The coupling magnet is to be cooled by two cryocoolers with a total cooling capacity of 3 W at 4.2 K. In order to keep a certain operating temperature margin, the most important is to reduce the heat leakage imposed on cold surfaces of coil cold mass assembly. An ntermediate temperature shield system placed between the coupling coil and warm vacuum chamber is adopted. The shield system consists of upper neck shield, main shields, flexible connections and eight supports, which is to be cooled by the first stage cold heads of two ryocoolers with cooling capacity of 55 W at 60 K each. The maximum temperature difference on the shields should be less than 20 K, so the thermal analyses for the shields with different thicknesses, materials, flexible connections for shields' cooling and structure design for heir supports were carried out. 1100 Al is finally adopted and the maximum temperature difference is around 15 K with 4 mm shield thickness. The paper is to present detailed analyses on the shield system design.

  15. The shielding calculation for the CN guide shielding assembly in HANARO

    International Nuclear Information System (INIS)

    Kim, H. S.; Lee, B. C.; Lee, K. H.; Kim, H.

    2006-01-01

    The cold neutron research facility in HANARO is under construction. The area including neutron guides and rotary shutter in the reactor hall should be shielded by the guide shielding assembly which is constructed of heavy concrete blocks and structure. The guide shielding assembly is divided into 2 parts, A and B. Part A is about 6.4 meters apart from the reactor biological shield and it is constructed of heavy concrete blocks whose density is above 4.0g/cm 3 . And part B is a fixed heavy concrete structure whose density is above 3.5g/cm 3 . The rotary shutter is also made with heavy concrete whose density is above 4.0g/cm 3 and includes 5 neutron guides inside. It can block the neutron beam by rotating when CNS is not operating. The dose criterion outside the guide shielding assembly is established as 12.5 μSv/hr which is also applied to reactor shielding in HANARO

  16. Application of Advanced Radiation Shielding Materials to Inflatable Structures, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This innovation is a weight-optimized, inflatable structure that incorporates radiation shielding materials into its construction, for use as a habitation module or...

  17. Shielded serpentine traveling wave tube deflection structure

    Science.gov (United States)

    Hudson, C.L.; Spector, J.

    1994-12-27

    A shielded serpentine slow wave deflection structure is disclosed having a serpentine signal conductor within a channel groove. The channel groove is formed by a serpentine channel in a trough plate and a ground plane. The serpentine signal conductor is supported at its ends by coaxial feed through connectors. A beam interaction trough intersects the channel groove to form a plurality of beam interaction regions wherein an electron beam may be deflected relative to the serpentine signal conductor. 4 figures.

  18. Radiation shielding material

    International Nuclear Information System (INIS)

    Matsumoto, Akio; Isobe, Eiji.

    1976-01-01

    Purpose: To increase the shielding capacity of the radiation shielding material having an abundant flexibility. Constitution: A mat consisting of a lead or lead alloy fibrous material is covered with a cloth, and the two are made integral by sewing in a kilted fashion by using a yarn. Thereafter, the system is covered with a gas-tight film or sheet. The shielding material obtained in this way has, in addition to the above merits, advantages in that (1) it is free from restoration due to elasticity so that it can readily seal contaminants, (2) it can be used in a state consisting of a number of overlapped layers, (3) it fits the shoulder well and is readily portable and (4) it permits attachment of fasteners or the like. (Ikeda, J.)

  19. Transparent Metal-Salt-Filled Polymeric Radiation Shields

    Science.gov (United States)

    Edwards, David; Lennhoff, John; Harris, George

    2003-01-01

    "COR-RA" (colorless atomic oxygen resistant -- radiation shield) is the name of a transparent polymeric material filled with x-ray-absorbing salts of lead, bismuth, cesium, and thorium. COR-RA is suitable for use in shielding personnel against bremsstrahlung radiation from electron-beam welding and industrial and medical x-ray equipment. In comparison with lead-foil and leaded-glass shields that give equivalent protection against x-rays (see table), COR-RA shields are mechanically more durable. COR-RA absorbs not only x-rays but also neutrons and rays without adverse effects on optical or mechanical performance. The formulation of COR-RA with the most favorable mechanical-durability and optical properties contains 22 weight percent of bismuth to absorb x-rays, plus 45 atomic percent hydrogen for shielding against neutrons.

  20. Development of a low activation concrete shielding wall by multi-layered structure for a fusion reactor

    International Nuclear Information System (INIS)

    Sato, Satoshi; Maegawa, Toshio; Yoshimatsu, Kenji; Sato, Koichi; Nonaka, Akira; Takakura, Kosuke; Ochiai, Kentaro; Konno, Chikara

    2011-01-01

    A multi-layered concrete structure has been developed to reduce induced activity in the shielding for neutron generating facilities such as a fusion reactor. The multi-layered concrete structure is composed of: (1) an inner low activation concrete, (2) a boron-doped low activation concrete as the second layer, and (3) ordinary concrete as the outer layer of the neutron shield. With the multi-layered concrete structure the volume of boron is drastically decreased compared to a monolithic boron-doped concrete. A 14 MeV neutron shielding experiment with multi-layered concrete structure mockups was performed at FNS and several reaction rates and induced activity in the mockups were measured. This demonstrated that the multi-layered concrete effectively reduced low energy neutrons and induced activity.

  1. Shielding Calculations for PUSPATI TRIGA Reactor (RTP) Fuel Transfer Cask with Micro shield

    International Nuclear Information System (INIS)

    Nurhayati Ramli; Ahmad Nabil Abdul Rahim; Ariff Shah Ismail

    2011-01-01

    The shielding calculations for RTP fuel transfer cask was performed by using computer code Micro shield 7.02. Micro shield is a computer code designed to provide a model to be used for shielding calculations. The results of the calculations can be obtained fast but the code is not suitable for complex geometries with a shielding composed of more than one material. Nevertheless, the program is sufficient for As Low As Reasonable Achievable (ALARA) optimization calculations. In this calculation, a geometry based on the conceptual design of RTP fuel transfer cask was modeled. Shielding material used in the calculations were lead (Pb) and stainless steel 304 (SS304). The results obtained from these calculations are discussed in this paper. (author)

  2. Reactor head shielding apparatus

    International Nuclear Information System (INIS)

    Schukei, G.E.; Roebelen, G.J.

    1992-01-01

    This patent describes a nuclear reactor head shielding apparatus for mounting on spaced reactor head lifting members radially inwardly of the head bolts. It comprises a frame of sections for mounting on the lifting members and extending around the top central area of the head, mounting means for so mounting the frame sections, including downwardly projecting members on the frame sections and complementary upwardly open recessed members for fastening to the lifting members for receiving the downwardly projecting members when the frame sections are lowered thereto with lead shielding supported thereby on means for hanging lead shielding on the frame to minimize radiation exposure or personnel working with the head bolts or in the vicinity thereof

  3. Practical radiation shielding for biomedical research

    International Nuclear Information System (INIS)

    Klein, R.C.; Reginatto, M.; Party, E.; Gershey, E.L.

    1990-01-01

    This paper reports on calculations which exist for estimating shielding required for radioactivity; however, they are often not applicable for the radionuclides and activities common in biomedical research. A variety of commercially available Lucite shields are being marketed to the biomedical community. Their advertisements may lead laboratory workers to expect better radiation protection than these shields can provide or to assume erroneously that very weak beta emitters require extensive shielding. The authors have conducted a series of shielding experiments designed to simulate exposures from the amounts of 32 P, 51 Cr and 125 I typically used in biomedical laboratories. For most routine work, ≥0.64 cm of Lucite covered with various thicknesses of lead will reduce whole-body occupational exposure rates of < 1mR/hr at the point of contact

  4. RadShield: semiautomated shielding design using a floor plan driven graphical user interface.

    Science.gov (United States)

    DeLorenzo, Matthew C; Wu, Dee H; Yang, Kai; Rutel, Isaac B

    2016-09-08

    The purpose of this study was to introduce and describe the development of RadShield, a Java-based graphical user interface (GUI), which provides a base design that uniquely performs thorough, spatially distributed calculations at many points and reports the maximum air-kerma rate and barrier thickness for each barrier pursuant to NCRP Report 147 methodology. Semiautomated shielding design calculations are validated by two approaches: a geometry-based approach and a manual approach. A series of geometry-based equations were derived giv-ing the maximum air-kerma rate magnitude and location through a first derivative root finding approach. The second approach consisted of comparing RadShield results with those found by manual shielding design by an American Board of Radiology (ABR)-certified medical physicist for two clinical room situations: two adjacent catheterization labs, and a radiographic and fluoroscopic (R&F) exam room. RadShield's efficacy in finding the maximum air-kerma rate was compared against the geometry-based approach and the overall shielding recommendations by RadShield were compared against the medical physicist's shielding results. Percentage errors between the geometry-based approach and RadShield's approach in finding the magnitude and location of the maximum air-kerma rate was within 0.00124% and 14 mm. RadShield's barrier thickness calculations were found to be within 0.156 mm lead (Pb) and 0.150 mm lead (Pb) for the adjacent catheteriza-tion labs and R&F room examples, respectively. However, within the R&F room example, differences in locating the most sensitive calculation point on the floor plan for one of the barriers was not considered in the medical physicist's calculation and was revealed by the RadShield calculations. RadShield is shown to accurately find the maximum values of air-kerma rate and barrier thickness using NCRP Report 147 methodology. Visual inspection alone of the 2D X-ray exam distribution by a medical physicist may not

  5. Structural and Shielding Safety of a Transport Package for Radioisotope Sealed Source Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Kiseog; Cho, Ilje; Kim, Donghak [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    2006-07-01

    As some kinds of radioisotope (RI) sealed source are produced by HANARO research reactor, a demand of RI transport package is increasing gradually. Foreign countries, which produce the various RIs, have the intrinsic model of the RI transport package. It is necessary to develop a RI and its transport package simultaneously. It is difficult to design a shielding part for this transport package because the passage for this source assembly should be provided from the center of shielding part to the outside of the package. In order to endure the accident conditions such as a 9 m drop and puncture, this transport package consists of the guide tubes, a gamma shield and a shock absorber. This paper describe that a shielding and structural safety of RI sealed source transport package are evaluated under the accident conditions.

  6. Structural and Shielding Safety of a Transport Package for Radioisotope Sealed Source Assembly

    International Nuclear Information System (INIS)

    Seo, Kiseog; Cho, Ilje; Kim, Donghak

    2006-01-01

    As some kinds of radioisotope (RI) sealed source are produced by HANARO research reactor, a demand of RI transport package is increasing gradually. Foreign countries, which produce the various RIs, have the intrinsic model of the RI transport package. It is necessary to develop a RI and its transport package simultaneously. It is difficult to design a shielding part for this transport package because the passage for this source assembly should be provided from the center of shielding part to the outside of the package. In order to endure the accident conditions such as a 9 m drop and puncture, this transport package consists of the guide tubes, a gamma shield and a shock absorber. This paper describe that a shielding and structural safety of RI sealed source transport package are evaluated under the accident conditions

  7. Structural analysis of the Passive Magnetic Shield for the ITER Heating Neutral Beam Injector system

    Energy Technology Data Exchange (ETDEWEB)

    Cabrera, Santiago, E-mail: santiago.cabrera@ciemat.es [CIEMAT Laboratorio Nacional de Fusión, Avda. Complutense 40, 28040 Madrid (Spain); Rincón, Esther; Ahedo, Begoña; Alonso, Javier; Barrera, Germán; Ramos, Francisco; Ríos, Luis [CIEMAT Laboratorio Nacional de Fusión, Avda. Complutense 40, 28040 Madrid (Spain); El-Ouazzani, Anass; García, Pablo [ITER Organization, Route de Vinon-sur-Verdon – CS 90 046, 13067 St Paul Lez Durance Cedex (France); Agarici, Gilbert [Fusion for Energy, Josep Pla 2, Torres Diagonal Litoral B3 – 07/08, 08019 Barcelona (Spain)

    2015-10-15

    The ITER Passive Magnetic Shield (PMS) main function is to protect the Neutral Beam Injector (NBI) from the external magnetic field coming from the tokamak, and to shield the NB cell from the radiation coming from all activated components. The shielding from the external magnetic field is performed in association with the Active Compensation Cooled Correction Coils (ACCC). The Bushing and Transmission Line (TL) PMS also provides structural support for HV bushing, allowing its maintenance and providing air sealing function between NBI cell and High Voltage deck room. The paper summarizes the structural analyses performed in order to evaluate the mechanical behaviour of the HNB PMS under operation combined with seismic event. The RCC-MR Code is used to validate the design, assuming creep is negligible, since the structure is expected to be at room temperature. P-type damage is assessed.

  8. Structural evolution of Halaban Area, Eastern Arabian Shield, Saudi Arabia

    Science.gov (United States)

    Al-Amri, Yousef; Kassem1, Osama M. K.

    2017-04-01

    Neoproterozoic basement complex comprises a metamorphic/igneous suite (Abt schist and sheared granitoids) with syn-accretionary transpressive structures, unconformably overlain by a post-amalgamation volcanosedimentary sequence. This study aims to attempt to exposed post-accretionary thrusting and thrust-related structures at Halaban area, Eastern Arabian Shield. The Rf/ϕ and Fry methods are utilized on quartz and feldspar porphyroclasts, as well as on mafic crystals, such as hornblende and biotite, in eighteen samples. The X/Z axial ratios range from 1.12 to 4.99 for Rf/ϕ method and from 1.65 to 4.00 for Fry method. The direction of finite strain for the long axes displays clustering along the WNW trend (occasionally N) with slight plunging. Finite strain accumulated without any significant volume change contemporaneously with syn-accretionary transpressive structures. It indicates that the contacts between various lithological units in the Halaban area were formed under brittle to semi-ductile deformation conditions. The penetrative subhorizontal foliation was concurrent with thrusting and shows nearly the same attitudes of tectonic contacts with the overlying nappes. Keywords: Finite strain analysis, volcanosedimentary sequence, Halaban area, Eastern Arabian Shield, Saudi Arabia.

  9. Radiation shielding curtain

    International Nuclear Information System (INIS)

    Winkler, N.T.

    1976-01-01

    A radiation shield is described in the form of a stranded curtain made up of bead-chains whose material and geometry are selected to produce a cross-sectional density that is the equivalent of 0.25 mm or more of lead and which curtain may be mounted on various radiological devices to shield against scattered radiation while offering a minimum of obstruction to the radiologist

  10. Shielding effect of lead glasses on radiologists' eye lens exposure in interventional procedures

    International Nuclear Information System (INIS)

    Hu, Panpan; Kong, Yan; Chen, Bo; Liu, Qianqian; Zhuo, Weihai; Liu, Haikuan

    2017-01-01

    To study the shielding effect of radiologists' eye lens with lead glasses of different equivalent thicknesses and sizes in interventional radiology procedures. Using the human voxel phantom with a more accurate model of the eye and MCNPX software, eye lens doses of the radiologists who wearing different kinds of lead glasses were simulated, different beam projections were taken into consideration during the simulation. Measurements were also performed with the physical model to verify simulation results. Simulation results showed that the eye lens doses were reduced by a factor from 3 to 9 when wearing a 20 cm"2-sized lead glasses with the equivalent thickness ranging from 0.1 to 1.0 mm Pb. The increase of dose reduction factor (DRF) was not significant whenever increase the lead equivalent of glasses of which larger than 0.35 mm. Furthermore, the DRF was proportional to the size of glass lens from 6 to 30 cm"2 with the same lead equivalent. The simulation results were in well agreements with the measured ones. For more reasonable and effective protection of the eye lens of interventional radiologists, a pair of glasses with a lead equivalent of 0.5 mm Pb and large-sized (at least 27 cm"2 per glass) lens are recommended (authors)

  11. Natural fibre high-density polyethylene and lead oxide composites for radiation shielding

    CERN Document Server

    El-Sayed, A; Ismail, M R

    2003-01-01

    Study has been made of the radiation shielding provided by recycled agricultural fibre and industrial plastic wastes produced as composite materials. Fast neutron and gamma-ray spectra behind composites of fibre-plastic (rho = 1.373 g cm sup - sup 3) and fibre-plastic-lead (rho = 2.756 g cm sup - sup 3) have been measured using a collimated reactor beam and neutron-gamma spectrometer with a stilbene scintillator. The pulse shape discriminating technique based on the zero-cross-over method was used to discriminate between neutron and gamma-ray pulses. Slow neutron fluxes have been measured using a collimated reactor beam and BF sub 3 counter, leading to determination of the macroscopic cross-section (SIGMA). The removal cross-sections (SIGMA sub R) of fast neutrons have been determined from measured results and elemental composition of the composites. For gamma-rays, total linear attenuation coefficients (mu) and total mass attenuation coefficients (mu/rho) have been determined from use of the XCOM code and me...

  12. Nano lead oxide and epdm composite for development of polymer based radiation shielding material: Gamma irradiation and attenuation tests

    Science.gov (United States)

    Özdemir, T.; Güngör, A.; Akbay, I. K.; Uzun, H.; Babucçuoglu, Y.

    2018-03-01

    It is important to have a shielding material that is not easily breaking in order to have a robust product that guarantee the radiation protection of the patients and radiation workers especially during the medical exposure. In this study, nano sized lead oxide (PbO) particles were used, for the first time, to obtain an elastomeric composite material in which lead oxide nanoparticles, after the surface modification with silane binding agent, was used as functional material for radiation shielding. In addition, the composite material including 1%, 5%, 10%, 15% and 20% weight percent nano sized lead oxide was irradiated with doses of 81, 100 and 120 kGy up to an irradiation period of 248 days in a gamma ray source with an initial dose rate of 21.1 Gy/h. Mechanical, thermal properties of the irradiated materials were investigated using DSC, DMA, TGA and tensile testing and modifications in thermal and mechanical properties of the nano lead oxide containing composite material via gamma irradiation were reported. Moreover, effect of bismuth-III oxide addition on radiation attenuation of the composite material was investigated. Nano lead oxide and bismuth-III oxide particles were mixed with different weight ratios. Attenuation tests have been conducted to determine lead equivalent values for the developed composite material. Lead equivalent thickness values from 0.07 to 0.65 (2-6 mm sample thickness) were obtained.

  13. Measurement of radiation shielding properties of polymer composites by using HPGe detector

    International Nuclear Information System (INIS)

    Gupta, Anil; Pillay, H.C.M.; Kale, P.K.; Datta, D.; Suman, S.K.; Gover, V.

    2014-01-01

    Lead is the most common radiation shield and its composite with polymers can be used as flexible radiation shields for different applications. However, lead is very hazardous and has been found to be associated with neurological disorders, kidney failure and hematotoxicity. Lead free radiation shield material has been developed by synthesizing radiation cross linked PDMS/Bi 2 O 3 polymer composites. In order to have a lead free radiation shield the relevant shielding properties such as linear attenuation, half value thickness (HVT) and tenth value thickness (TVT) have been measured by using HPGe detector. The present study describes the methodology of measurement of the shielding properties of the lead free shield material. In the measurement gamma energies such as 59.537 keV ( 241 Am), 122.061 keV and 136.474 keV ( 57 Co) are taken into consideration

  14. Scintillation counter, segmented shield

    International Nuclear Information System (INIS)

    Olson, R.E.; Thumim, A.D.

    1975-01-01

    A scintillation counter, particularly for counting gamma ray photons, includes a massive lead radiation shield surrounding a sample-receiving zone. The shield is disassembleable into a plurality of segments to allow facile installation and removal of a photomultiplier tube assembly, the segments being so constructed as to prevent straight-line access of external radiation through the shield into radiation-responsive areas. Provisions are made for accurately aligning the photomultiplier tube with respect to one or more sample-transmitting bores extending through the shield to the sample receiving zone. A sample elevator, used in transporting samples into the zone, is designed to provide a maximum gamma-receiving aspect to maximize the gamma detecting efficiency. (U.S.)

  15. Study on preparation of ultrafine lead tungstate for radiation protection and γ-ray shielding of the gloves

    International Nuclear Information System (INIS)

    Du Licheng; He Ping; Zhou Yuanlin; Song Kaiping; Yang Kuihua

    2012-01-01

    Lead tungstate combines the radiation shielding properties of tungsten and lead, and it is quite distinctive to manufacture lead tungstate with ultra-fine granularity to enhance its capacity of radiation shielding. The grain size of lead tungstate has direct impact on the ability of its protection from radioactive materials. the smaller the grain size and more uniform dispersion of lead tungstate, the better protective ability it is going to be. In this paper, soft-template synthesis was introduced to prepare ultra-fine PbWO 4 . Rigorous experiment conditions are settled to ensure the access to obtain ultra-fine, homogeneous lead tungstate product, and it is better than other physical and chemical preparation methods. The surface-active agent for the soft template, with S-60 for the water system W/O microemulsion zone, was used to synthesize successfully ultra-fine PbWO 4 . It was shown that dispersing agent S-60 in the soft template method produced ultra-fine PbWO 4 with uniform granularity distribution. By using orthogonal experimental method, the best experimental conditions were obtained as follows: S-60 as surfactant dispersant with diluted 30 times concentration, solutions with pH9, 0.01 mol/L concentration of reactant, 1300 rpm of stirring speed and slowly adding drops of Na 2 WO 4 solution into Pb (Ac) 2 solution. Based on the optimal experimental conditions, the product of ultra-fine product for the anti-radiation protection filler has been made. The fine packing for the preparation of tungsten the gamma rays on the gloves is an average capacity of 5% or so. (authors)

  16. Acoustic metacages for sound shielding with steady air flow

    Science.gov (United States)

    Shen, Chen; Xie, Yangbo; Li, Junfei; Cummer, Steven A.; Jing, Yun

    2018-03-01

    Conventional sound shielding structures typically prevent fluid transport between the exterior and interior. A design of a two-dimensional acoustic metacage with subwavelength thickness which can shield acoustic waves from all directions while allowing steady fluid flow is presented in this paper. The structure is designed based on acoustic gradient-index metasurfaces composed of open channels and shunted Helmholtz resonators. In-plane sound at an arbitrary angle of incidence is reflected due to the strong parallel momentum on the metacage surface, which leads to low sound transmission through the metacage. The performance of the proposed metacage is verified by numerical simulations and measurements on a three-dimensional printed prototype. The acoustic metacage has potential applications in sound insulation where steady fluid flow is necessary or advantageous.

  17. Radiation shielding

    International Nuclear Information System (INIS)

    Aitken, D.

    1979-01-01

    Shields for equipment in which ionising radiation is associated with high electrical gradients, for example X-ray tubes and particle accelerators, incorporate a radiation-absorbing metal, as such or as a compound, and are electrically non-conducting and can be placed in the high electrical gradient region of the equipment. Substances disclosed include dispersions of lead, tungsten, uranium or oxides of these in acrylics polyesters, PVC, ABS, polyamides, PTFE, epoxy resins, glass or ceramics. The material used may constitute an evacuable enclosure of the equipment or may be an external shield thereof. (U.K.)

  18. Experimental studies of dynamic impact response with scale models of lead shielded radioactive material shipping containers

    International Nuclear Information System (INIS)

    Robinson, R.A.; Hadden, J.A.; Basham, S.J.

    1978-01-01

    Preliminary experimental studies of dynamic impact response of scale models of lead-shielded radioactive material shipping containers are presented. The objective of these studies is to provide DOE/ECT with a data base to allow the prediction of a rational margin of confidence in overviewing and assessing the adequacy of the safety and environmental control provided by these shipping containers. Replica scale modeling techniques were employed to predict full scale response with 1/8, 1/4, and 1/2 scale models of shipping containers that are used in the shipment of spent nuclear fuel and high level wastes. Free fall impact experiments are described for scale models of plain cylindrical stainless steel shells, stainless steel shells filled with lead, and replica scale models of radioactive material shipping containers. Dynamic induced strain and acceleration measurements were obtained at several critical locations on the models. The models were dropped from various heights, attitudes to the impact surface, with and without impact limiters and at uniform temperatures between -40 and 175 0 C. In addition, thermal expansion and thermal gradient induced strains were measured at -40 and 175 0 C. The frequency content of the strain signals and the effect of different drop pad compositions and stiffness were examined. Appropriate scale modeling laws were developed and scaling techniques were substantiated for predicting full scale response by comparison of dynamic strain data for 1/8, 1/4, and 1/2 scale models with stainless steel shells and lead shielding

  19. Thermal-structural analysis for ITER in-wall shielding block

    International Nuclear Information System (INIS)

    Hao Junchuan; Song Yuntao; Wu Weiyue; Du Shuangsong; Wang, X.; Ioki, K.

    2012-01-01

    Highlights: ► IWS blocks shall withstand various types of mechanical loads including EM loads, inertial loads and thermal loads. ► Due to the complicated geometry, the finite element method is the suitable tool to solve the problem. ► Contact element has been selected to simulate the friction between the different components. ► At baking phase, secondary stresses due to preloading and temperature difference predominate in the total stress. ► At plasma operation phase, secondary stresses due to preloading and thermal loads were deducted from the total stresses. - Abstract: In order to verify the design strength of the in-wall shielding (IWS) blocks of the ITER, thermal-structural analyses of one IWS block under vacuum vessel (VV) baking and plasma operation conditions have been respectively performed with finite element (FE) method. Among the complicated operation scenarios of the ITER, two critical types of combined loads required by the load specification of IWS were applied on the shielding block. The stress of the block is judged by American Society of Mechanical Engineers (ASME) criterion. Results show that the structure of this block has enough safety margin, and it also supplies detailed information of the stress distribution in concerned region under certain loads.

  20. Shielding evaluation of moving bed onion irradiator by radiometry

    International Nuclear Information System (INIS)

    Venkataramani, R.; Sangurdekar, P.R.; Sarangapani, R.; Raipurkar, D.R.; Mehta, S.K.; Shastri, S.P.; Patil, K.B.; Bongirwar, D.R.

    1994-01-01

    A moving bed onion irradiator made from m.s. cladded lead slab shields designed to hold 20 kCi of 60 Co source was evaluated by radiometry with an 8 Ci 60 Co source from CRC-2 radiography camera. Some shielding losses in the irradiator noted by radiometry could be visualized by a thermocole model of the complex shielding assembly. These were rectified by appropriate lead filling. Significant shielding losses noted at cladding layer positions of slabs were attributed to lack of interlocking features in the slabs. These had to be rectified by provision of 3 TVL of additional all round shielding supplemented by local shielding at some positions. (author). 1 fig., 1 tab

  1. Magnetic shielding for superconducting RF cavities

    Science.gov (United States)

    Masuzawa, M.; Terashima, A.; Tsuchiya, K.; Ueki, R.

    2017-03-01

    Magnetic shielding is a key technology for superconducting radio frequency (RF) cavities. There are basically two approaches for shielding: (1) surround the cavity of interest with high permeability material and divert magnetic flux around it (passive shielding); and (2) create a magnetic field using coils that cancels the ambient magnetic field in the area of interest (active shielding). The choice of approach depends on the magnitude of the ambient magnetic field, residual magnetic field tolerance, shape of the magnetic shield, usage, cost, etc. However, passive shielding is more commonly used for superconducting RF cavities. The issue with passive shielding is that as the volume to be shielded increases, the size of the shielding material increases, thereby leading to cost increase. A recent trend is to place a magnetic shield in a cryogenic environment inside a cryostat, very close to the cavities, reducing the size and volume of the magnetic shield. In this case, the shielding effectiveness at cryogenic temperatures becomes important. We measured the permeabilities of various shielding materials at both room temperature and cryogenic temperature (4 K) and studied shielding degradation at that cryogenic temperature.

  2. Shielding member for thermonuclear device

    Energy Technology Data Exchange (ETDEWEB)

    Onozuka, Masanori

    1997-06-30

    In a thermonuclear device for shielding fast neutrons by shielding members disposed in a shielding vessel (vacuum vessel and structures such as a blanket disposed in the vacuum vessel), the shielding member comprises a large number of shielding wires formed fine and short so as to have elasticity. The shielding wires are sealed in a shielding vessel together with water, and when the width of the shielding vessel is changed, the shielding wires follow after the change of the width while elastically deforming in the shielding vessel, so that great stress and deformation are not formed thereby enabling to improve reliability. In addition, the length, the diameter and the shape of each of the shielding wires can be selected in accordance with the shielding space of the shielding vessel. Even if the shape of the shielding vessel is complicated, the shielding wires can be inserted easily. Accordingly, the filling rate of the shielding members can be changed easily. It can be produced more easily compared with a conventional spherical pebbles. It can be produced more easily than existent spherical shielding pebbles thereby enabling to reduce the production cost. (N.H.)

  3. Shielding of the contralateral breast during tangential irradiation.

    Science.gov (United States)

    Goffman, Thomas E; Miller, Michael; Laronga, Christine; Oliver, Shelly; Wong, Ping

    2004-08-01

    The purpose of this study was to investigate both optimal and practical contralateral breast shielding during tangential irradiation in young patients. A shaped sheet of variable thickness of lead was tested on a phantom with rubber breasts, and an optimized shield was created. Testing on 18 consecutive patients 50 years or younger showed shielding consistently reduced contralateral breast dose to at least half, with small additional reduction after removal of the medial wedge. For younger patients in whom radiation exposure is of considerable concern, a simple shield of 2 mm lead thickness proved practical and effective.

  4. An investigation of dose changes for therapeutic kilovoltage x-ray beams with underlying lead shielding

    International Nuclear Information System (INIS)

    Hill, Robin; Healy, Brendan; Holloway, Lois; Baldock, Clive

    2007-01-01

    Kilovoltage x-ray beams are used to treat cancer on or close to the skin surface. Many clinical cases use high atomic number materials as shielding to reduce dose to underlying healthy tissues. In this work, we have investigated the effect on both the surface dose and depth doses in a water phantom with lead shielding at depth in the phantom. The EGSnrc Monte Carlo code was used to simulate the water phantom and to calculate the surface doses and depth doses using primary x-ray beam spectra derived from an analytical model. The x-ray beams were in the energy range of 75-135 kVp with field sizes of 2, 5 and 8 cm diameter. The lead sheet was located beneath the water surface at depths ranging from 0.5-7.5 cm. The surface dose decreased as the lead was positioned closer to the water surface and as the field size was increased. The variation in surface dose as a function of x-ray beam energy was only small but the maximum reduction occurred for the 100 kVp x-ray beam. For the 8 cm diameter field with the lead at 1 cm depth and using the 100 kVp x-ray beam, the surface dose was reduced to 0.898 of the surface dose in the water phantom only. Measured surface dose changes, using a Farmer-type ionization chamber, agreed with the Monte Carlo calculated doses. Calculated depth doses in water with a lead sheet positioned below the surface showed that the dose fall-off increased as the lead was positioned closer to the water surface as compared to the depth dose in the water phantom only. Monte Carlo calculations of the total x-ray beam spectrum at the water surface showed that the total fluence decreased due to a reduction in backscatter from within the water and very little backscatter from the lead. The mean energy of the x-ray spectrum varied less than 1 keV, with the lead at 1 cm beneath the water phantom surface. As the Monte Carlo calculations showed good agreement with the measured results, this method can be used to verify surface dose changes in clinical situations

  5. Neutron shieldings

    International Nuclear Information System (INIS)

    Tarutani, Kohei

    1979-01-01

    Purpose: To decrease the stresses resulted by the core bendings to the base of an entrance nozzle. Constitution: Three types of round shielding rods of different diameter are arranged in a hexagonal tube. The hexagonal tube is provided with several spacer pads receiving the loads from the core constrain mechanism at its outer circumference, a handling head for a fuel exchanger at its top and an entrance nozzle for self-holding the neutron shieldings and flowing heat-removing coolants at its bottom. The diameters for R 1 , R 2 and R 3 for the round shielding rods are designed as: 0.1 R 1 2 1 and 0.2 R 1 2 1 . Since a plurality of shielding rods of small diameter are provided, soft structure are obtained and a plurality of coolant paths are formed. (Furukawa, Y.)

  6. Poster – 39: Using Optical Scanner and 3D Printer Technology to Create Lead Shielding for Radiotherapy of Facial Skin Cancer with Low Energy Photons

    International Nuclear Information System (INIS)

    Rickey, Daniel; Leylek, Ahmet; Dubey, Arbind; Sasaki, David; Harris, Chad; Butler, Jim; Sharma, Ankur; McCurdy, Boyd; Alpuche Aviles, Jorge E.

    2016-01-01

    Purpose: Treatment of skin cancers of the face using orthovoltage radiotherapy often requires lead shielding. However, creating a lead shield can be difficult because the face has complex and intricate contours. The traditional process involved creating a plaster mould of the patient’s face can be difficult for patients. Our goal was to develop an improved process by using an optical scanner and 3D printer technology. Methods: The oncologist defined the treatment field by drawing on each patient’s skin. Three-dimensional images were acquired using a consumer-grade optical scanner. A 3D model of each patient’s face was processed with mesh editing software before being printed on a 3D printer. Using a hammer, a 3 mm thick layer of lead was formed to closely fit the contours of the model. A hole was then cut out to define the field. Results: The lead shields created were remarkably accurate and fit the contours of the patients. The hole defining the field exposed only a minimally sized site to be exposed to radiation, while the rest of the face was protected. It was easy to obtain perfect symmetry for the definition of parallel opposed beams. Conclusion: We are routinely using this technique to build lead shielding that wraps around the patient as an alternative to cut-outs. We also use it for treatment of the tip of the nose using a parallel opposed pair beams with a wax nose block. We found this technique allows more accurate delineation of the cut-out and a more reproducible set-up.

  7. Poster – 39: Using Optical Scanner and 3D Printer Technology to Create Lead Shielding for Radiotherapy of Facial Skin Cancer with Low Energy Photons

    Energy Technology Data Exchange (ETDEWEB)

    Rickey, Daniel; Leylek, Ahmet; Dubey, Arbind; Sasaki, David; Harris, Chad; Butler, Jim; Sharma, Ankur; McCurdy, Boyd; Alpuche Aviles, Jorge E. [CancerCare Manitoba, CancerCare Manitoba, CancerCare Manitoba, CancerCare Manitoba, CancerCare Manitoba, CancerCare Manitoba, CancerCare Manitoba, CancerCare Manitoba, CancerCare Manitoba (Canada)

    2016-08-15

    Purpose: Treatment of skin cancers of the face using orthovoltage radiotherapy often requires lead shielding. However, creating a lead shield can be difficult because the face has complex and intricate contours. The traditional process involved creating a plaster mould of the patient’s face can be difficult for patients. Our goal was to develop an improved process by using an optical scanner and 3D printer technology. Methods: The oncologist defined the treatment field by drawing on each patient’s skin. Three-dimensional images were acquired using a consumer-grade optical scanner. A 3D model of each patient’s face was processed with mesh editing software before being printed on a 3D printer. Using a hammer, a 3 mm thick layer of lead was formed to closely fit the contours of the model. A hole was then cut out to define the field. Results: The lead shields created were remarkably accurate and fit the contours of the patients. The hole defining the field exposed only a minimally sized site to be exposed to radiation, while the rest of the face was protected. It was easy to obtain perfect symmetry for the definition of parallel opposed beams. Conclusion: We are routinely using this technique to build lead shielding that wraps around the patient as an alternative to cut-outs. We also use it for treatment of the tip of the nose using a parallel opposed pair beams with a wax nose block. We found this technique allows more accurate delineation of the cut-out and a more reproducible set-up.

  8. Shielding design for the target room of the proton accelerator research center

    International Nuclear Information System (INIS)

    Min, Y. S.; Lee, C. W.; Mun, K. J.; Nam, J.; Kim, J. Y.

    2010-01-01

    The Proton Engineering Frontier Project (PEFP) has been developing a 100-MeV proton linear accelerator. Also, PEFP has been designing the Proton Accelerator Research Center (PARC). In the Accelerator Tunnel and Beam Experiment Hall in PARC, 10 target rooms for the 20- and 100-MeV beamline facilities exist in the Beam Experiment Hall. For the 100-MeV target rooms during 100-MeV proton beam extraction, a number of high energy neutrons, ranging up to 100-MeV, are produced. Because of the high beam current and space limitations of each target room, the shielding design of each target room should be considered seriously. For the shielding design of the 100-MeV target rooms of the PEFP, a permanent and removable local shield structure was adopted. To optimize shielding performance, we evaluated four different shield materials (concrete, HDPE, lead, iron). From the shielding calculation results, we confirmed that the proposed shielding design made it possible to keep the dose rate below the 'as low as reasonably achievable (ALARA)' objective.

  9. Reduction of entrance surface dose depending on shielding methods for panoramagraphy

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jung Hyun; Han, DongKyoon [Dept. of Radiological Science, The Graduate School, Eulji University, Sungnam (Korea, Republic of); Kim, Sung Chul [Dept. of Radiological, Science Gachon, University, Incheon (Korea, Republic of)

    2015-09-15

    Panoramagraphy was the second most used intraoral radiography utilized in Korea, resulting in 17.8% in university dental hospitals, 24.8% in dental hospitals, and 31.4% in dental clinics. Depending on increased demand like orthodontics and implant, panoromagraphy tends to consistently increase. This study were used lead glasses and lead shielding to reduce unnecessary radiation to the eyeballs and thyroid. ESD was 41.4% when radiation was shielded with the lead glasses while reducing 47.3% of ESD by shielding the X-ray tube area with shielding lead. There was no statistically significant difference. The lead glasses is appropriated to reduce unnecessary radiation exposure to the eyeballs.

  10. Reduction of entrance surface dose depending on shielding methods for panoramagraphy

    International Nuclear Information System (INIS)

    Choi, Jung Hyun; Han, DongKyoon; Kim, Sung Chul

    2015-01-01

    Panoramagraphy was the second most used intraoral radiography utilized in Korea, resulting in 17.8% in university dental hospitals, 24.8% in dental hospitals, and 31.4% in dental clinics. Depending on increased demand like orthodontics and implant, panoromagraphy tends to consistently increase. This study were used lead glasses and lead shielding to reduce unnecessary radiation to the eyeballs and thyroid. ESD was 41.4% when radiation was shielded with the lead glasses while reducing 47.3% of ESD by shielding the X-ray tube area with shielding lead. There was no statistically significant difference. The lead glasses is appropriated to reduce unnecessary radiation exposure to the eyeballs

  11. Radiation safety aspects during nondestructive testing of reactor shielding components by gamma radiometry

    International Nuclear Information System (INIS)

    Viswanathan, S.; Jose, M.T.; Venkatraman, B.

    2016-01-01

    In nuclear facilities, effective shielding of radioactive components and structures are essential to ensure radiation protection to operating personnel. The shield structures are made of lead, steel and concrete with varying thickness of up to 1200 mm. It needs to be verified for shielding integrity, presence of voids, blowholes and defects to avoid exposure to workers and to public at large. Radiometry using gamma source serves as excellent tool for non-destructive examination of such structures and components. Gamma sources of high activity up to 50 Curies (gamma camera type) depending on the thickness of component have to be used. During the testing exposure to the operating personnel needs to be minimized, this requires certain safety procedures to be followed. This paper focuses the methodology to be adapted by means of selection of source, effective training of personnel, compliance with safety requirements and maintenance of source devices

  12. Shielding walls against ionizing radiation

    International Nuclear Information System (INIS)

    1993-05-01

    Hot-cell shielding walls consist of building blocks made of lead according to DIN 25407 part 1, and of special elements according to DIN 25407 part 2. Alpha-gamma cells can be built using elements for protective contamination boxes according to DIN 25480 part 1. This standards document intends to provide planning engineers, manufacturers, future users and the competent authorities and experts with a basis for the design of hot cells with lead shielding walls and the design of hot-cell equipment. (orig./HP) [de

  13. Design report for shielded glove box

    International Nuclear Information System (INIS)

    Ku, J. H.; Lee, J. C.; Seo, K. S.; Bang, K. S.; Lee, D. W.; Kim, J. H.; Min, D. K.; Park, S. W.

    1999-05-01

    For the examination of spent fuels and high radioactive specimens using a specially equipped scanning electron microscope, a shielded glove box was designed and constructed at PIE facility of KAERI. This glove box consisted of shielding walls, containment box, lead glasses, manipulators, gloves, ventilation systems, doors, hot-cell specimen cask adapter, etc. It was emphasized that both the easy operation and radiation safety are important factors in the shielded glove box were installed also considered as a important factor to build the basic concept of the assembling. Two sliding doors and one hinge-type door were installed for the easy installation, operation and maintenance of scanning electron microscope. Containment box which confines the radioactive material into the box consisted of reinforced transparent glasses, aluminum frames and stainless steel plate liner. Therefore everything beyond the containment box can be seen through the lead glass which installed at the front shielding wall. All shielding walls and doors were introduced separately into the room and assembled by bolting. (author). 3 refs., 5 tabs., 18 figs

  14. Shielding Effect of Lead Glasses on Radiologists' Eye Lens Exposure in Interventional Procedures.

    Science.gov (United States)

    Hu, Panpan; Kong, Yan; Chen, Bo; Liu, Qianqian; Zhuo, Weihai; Liu, Haikuan

    2017-04-20

    To study the shielding effect of radiologists' eye lens with lead glasses of different equivalent thicknesses and sizes in interventional radiology procedures. Using the human voxel phantom with a more accurate model of the eye and MCNPX software, eye lens doses of the radiologists who wearing different kinds of lead glasses were simulated, different beam projections were taken into consideration during the simulation. Measurements were also performed with the physical model to verify simulation results. Simulation results showed that the eye lens doses were reduced by a factor from 3 to 9 when wearing a 20 cm2-sized lead glasses with the equivalent thickness ranging from 0.1 to 1.0 mm Pb. The increase of dose reduction factor (DRF) was not significant whenever increase the lead equivalent of glasses of which larger than 0.35 mm. Furthermore, the DRF was proportional to the size of glass lens from 6 to 30 cm2 with the same lead equivalent. The simulation results were in well agreements with the measured ones. For more reasonable and effective protection of the eye lens of interventional radiologists, a pair of glasses with a lead equivalent of 0.5 mm Pb and large-sized (at least 27 cm2 per glass) lens are recommended. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. Shielding container for radioactive isotopes

    International Nuclear Information System (INIS)

    Sumi, Tetsuo; Tosa, Masayoshi; Hatogai, Tatsuaki.

    1975-01-01

    Object: To effect opening and closing bidirectional radiation used particularly for a gamma densimeter or the like by one operation. Structure: This device comprises a rotatable shielding body for receiving radioactive isotope in the central portion thereof and having at least two radiation openings through which radiation is taken out of the isotope, and a shielding container having openings corresponding to the first mentioned radiation openings, respectively. The radioactive isotope is secured to a rotational shaft of the shielding body, and the shielding body is rotated to register the openings of the shielding container with the openings of the shielding body or to shield the openings, thereby effecting radiation and cut off of gamma ray in the bidirection by one operation. (Kamimura, M.)

  16. Comparative evaluation of structural integrity for ITER blanket shield block based on SDC-IC and ASME code

    Energy Technology Data Exchange (ETDEWEB)

    Shim, Hee-Jin [ITER Korea, National Fusion Research Institute, 169-148 Gwahak-Ro, Yuseong-Gu, Daejeon (Korea, Republic of); Ha, Min-Su, E-mail: msha12@nfri.re.kr [ITER Korea, National Fusion Research Institute, 169-148 Gwahak-Ro, Yuseong-Gu, Daejeon (Korea, Republic of); Kim, Sa-Woong; Jung, Hun-Chea [ITER Korea, National Fusion Research Institute, 169-148 Gwahak-Ro, Yuseong-Gu, Daejeon (Korea, Republic of); Kim, Duck-Hoi [ITER Organization, Route de Vinon sur Verdon - CS 90046, 13067 Sant Paul Lez Durance (France)

    2016-11-01

    Highlights: • The procedure of structural integrity and fatigue assessment was described. • Case studies were performed according to both SDC-IC and ASME Sec. • III codes The conservatism of the ASME code was demonstrated. • The study only covers the specifically comparable case about fatigue usage factor. - Abstract: The ITER blanket Shield Block is a bulk structure to absorb radiation and to provide thermal shielding to vacuum vessel and external vessel components, therefore the most significant load for Shield Block is the thermal load. In the previous study, the thermo-mechanical analysis has been performed under the inductive operation as representative loading condition. And the fatigue evaluations were conducted to assure structural integrity for Shield Block according to Structural Design Criteria for In-vessel Components (SDC-IC) which provided by ITER Organization (IO) based on the code of RCC-MR. Generally, ASME code (especially, B&PV Sec. III) is widely applied for design of nuclear components, and is usually well known as more conservative than other specific codes. For the view point of the fatigue assessment, ASME code is very conservative compared with SDC-IC in terms of the reflected K{sub e} factor, design fatigue curve and other factors. Therefore, an accurate fatigue assessment comparison is needed to measure of conservatism. The purpose of this study is to provide the fatigue usage comparison resulting from the specified operating conditions shall be evaluated for Shield Block based on both SDC-IC and ASME code, and to discuss the conservatism of the results.

  17. Comparative evaluation of structural integrity for ITER blanket shield block based on SDC-IC and ASME code

    International Nuclear Information System (INIS)

    Shim, Hee-Jin; Ha, Min-Su; Kim, Sa-Woong; Jung, Hun-Chea; Kim, Duck-Hoi

    2016-01-01

    Highlights: • The procedure of structural integrity and fatigue assessment was described. • Case studies were performed according to both SDC-IC and ASME Sec. • III codes The conservatism of the ASME code was demonstrated. • The study only covers the specifically comparable case about fatigue usage factor. - Abstract: The ITER blanket Shield Block is a bulk structure to absorb radiation and to provide thermal shielding to vacuum vessel and external vessel components, therefore the most significant load for Shield Block is the thermal load. In the previous study, the thermo-mechanical analysis has been performed under the inductive operation as representative loading condition. And the fatigue evaluations were conducted to assure structural integrity for Shield Block according to Structural Design Criteria for In-vessel Components (SDC-IC) which provided by ITER Organization (IO) based on the code of RCC-MR. Generally, ASME code (especially, B&PV Sec. III) is widely applied for design of nuclear components, and is usually well known as more conservative than other specific codes. For the view point of the fatigue assessment, ASME code is very conservative compared with SDC-IC in terms of the reflected K_e factor, design fatigue curve and other factors. Therefore, an accurate fatigue assessment comparison is needed to measure of conservatism. The purpose of this study is to provide the fatigue usage comparison resulting from the specified operating conditions shall be evaluated for Shield Block based on both SDC-IC and ASME code, and to discuss the conservatism of the results.

  18. Design of auxiliary shield for remote controlled metallographic microscope

    International Nuclear Information System (INIS)

    Matsui, Hiroki; Okamoto, Hisato

    2014-06-01

    The remote controlled optical microscope installed in the lead cell at the Reactor Fuel Examination Facility (RFEF) in Japan Atomic Energy Agency (JAEA) has been upgraded to a higher performance unit to study the effect of the microstructural evolution in clad material on the high burn-up fuel behavior under the accident condition. The optical pass of the new microscope requires a new through hole in the shielding lead wall of the cell. To meet safety regulations, auxiliary lead shieldings were designed to cover the lost shielding function of the cell wall. Particle and Heavy Ion Transport Code System (PHITS) was used to calculate and determine the shape and setting positions of the shielding unit. Seismic assessments of the unit were also performed. (author)

  19. Design experience: CRBRP radiation shielding

    International Nuclear Information System (INIS)

    Disney, R.K.; Chan, T.C.; Gallo, F.G.; Hedgecock, L.R.; McGinnis, C.A.; Wrights, G.N.

    1978-11-01

    The Clinch River Breeder Reactor Plant (CRBRP) is being designed as a fast breeder demonstration project in the U.S. Liquid Metal Fast Breeder Reactor (LMFBR) program. Radiation shielding design of the facility consists of a comprehensive design approach to assure compliance with design and government regulatory requirements. Studies conducted during the CRBRP design process involved the aspects of radiation shielding dealing with protection of components, systems, and personnel from radiation exposure. Achievement of feasible designs, while considering the mechanical, structural, nuclear, and thermal performance of the component or system, has required judicious trade-offs in radiation shielding performance. Specific design problems which have been addressed are in-vessel radial shielding to protect permanent core support structures, flux monitor system shielding to isolate flux monitoring systems for extraneous background sources, reactor vessel support shielding to allow personnel access to the closure head during full power operation, and primary heat transport system pipe chaseway shielding to limit intermediate heat transport system sodium system coolant activation. The shielding design solutions to these problems defined a need for prototypic or benchmark experiments to provide assurance of the predicted shielding performance of selected design solutions and the verification of design methodology. Design activities of CRBRP plant components an systems, which have the potential for radiation exposure of plant personnel during operation or maintenance, are controlled by a design review process related to radiation shielding. The program implements design objectives, design requirements, and cost/benefit guidelines to assure that radiation exposures will be ''as low as reasonably achievable''

  20. Gonad shielding in computerized tomography

    International Nuclear Information System (INIS)

    Rockstroh, G.

    1984-01-01

    The reduction of gonadal dose by shielding of the gonads was investigated for a Somatom 2 using an anthropomorphic phantom. For small distances from the slice examined the gonadal dose results from intracorporal secondary radiation and is only insignificantly reduced by shielding. For greater distances shielding is relatively more effective, the gonadal dose however is small because of the approximately exponential decay. Shielding of the gonads therefore does not seem adequate for the reduction of gonadal dose. From dose measurements in cylinder phantoms of several diameters it appears that no different results would be obtained for children and young adults. An effective reduction of gonadal dose is only possible with lead capsules for males. (author)

  1. Hot Cell Window Shielding Analysis Using MCNP

    International Nuclear Information System (INIS)

    Pope, Chad L.; Scates, Wade W.; Taylor, J. Todd

    2009-01-01

    The Idaho National Laboratory Materials and Fuels Complex nuclear facilities are undergoing a documented safety analysis upgrade. In conjunction with the upgrade effort, shielding analysis of the Fuel Conditioning Facility (FCF) hot cell windows has been conducted. This paper describes the shielding analysis methodology. Each 4-ft thick window uses nine glass slabs, an oil film between the slabs, numerous steel plates, and packed lead wool. Operations in the hot cell center on used nuclear fuel (UNF) processing. Prior to the shielding analysis, shield testing with a gamma ray source was conducted, and the windows were found to be very effective gamma shields. Despite these results, because the glass contained significant amounts of lead and little neutron absorbing material, some doubt lingered regarding the effectiveness of the windows in neutron shielding situations, such as during an accidental criticality. MCNP was selected as an analysis tool because it could model complicated geometry, and it could track gamma and neutron radiation. A bounding criticality source was developed based on the composition of the UNF. Additionally, a bounding gamma source was developed based on the fission product content of the UNF. Modeling the windows required field inspections and detailed examination of drawings and material specifications. Consistent with the shield testing results, MCNP results demonstrated that the shielding was very effective with respect to gamma radiation, and in addition, the analysis demonstrated that the shielding was also very effective during an accidental criticality.

  2. A study of the effect of intermediate structure in the fission cross section of 239Pu on self-shielding factors

    International Nuclear Information System (INIS)

    Ganesan, S.

    1978-01-01

    A set of energy dependent fission widths of 1 + spin state corresponding to the recommended fission cross sections of Sowerby et al is evaluated by adjustment in the energy region 600 ev to 25 Kev. Corresponding to these mean fission widths of 1 + spin state, the intermediate resonance parameters based on Weigmann's formulation of Struitinsky's double humped fission barrier model are then obtained. Pseudorandom resonances are generated with and without the intermediate structure in the mean fission but leading to the same value of infinite dilution fission cross section. The effect of the intermediate structure on the self shielding factors was then investigated. (author)

  3. Determination of ICRF antenna fields in the vicinity of a 3-D Faraday shield structure

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, P M; Rothe, K E; Whealton, J H; Shepard, T D [Oak Ridge National Lab., TN (USA)

    1990-04-01

    A three-dimensional (3-D) magnetostatic analysis developed at Oak Ridge National Laboratory has been used to calculate the electromagnetic transmission properties of representative Faraday shield designs. The analysis uses the long-wavelength approximation to obtain a 3-D Laplace solution for the magnetic scalar potential over one poloidal period of the Faraday shield, from which the complete magnetic field distribution may be obtained. Once the magnetic field distributions in the presence and absence of a Faraday shield are known, the flux transmission coefficient can be found, as well as any change in the distributed inductance of the current strap. The distrbuted capacitance of the strap can be found from an analogous 3-D electrostatic calculation, enabling the phase velocity of the slow-wave structure to be determined. Power dissipation in the shield may be estimated by equating the surface current on a perfect conductor with the surface magnetic field and using this surface current in conjunction with the finite conductivities of the shield materials to obtain the power distribution due to eddy current heating. (orig.).

  4. Development and application of high performance liquid shielding materials

    International Nuclear Information System (INIS)

    Miura, Toshimasa; Omata, Sadao; Otano, Naoteru; Hirao, Yoshihiro; Kanai, Yasuji

    1998-01-01

    Development of liquid shielding material with good performance for neutron and γ-ray was investigated. Lead, hydrogen and boron were selected as the elements of shielding materials which were made by the ultraviolet curing method. Good performance shielding materials with about 1 mm width to neutron and gamma ray were produced by mixing lead, boron compound and ultraviolet curing monomer with many hydrogens. The shielding performance was the same as a concrete with two times width. The activation was very small such as 1/10 6 -1/10 8 of the standard concrete. The weight and the external appearance did not charged from room temperature to 100degC. Polyfunctional monomer had good thermal resistance. This shielding material was applied to double bending cylindrical duct and annulus ring duct. The results proved the shielding materials developed had good performance. (S.Y.)

  5. Shielded scanning electron microscope for radioactive samples

    International Nuclear Information System (INIS)

    Crouse, R.S.; Parsley, W.B.

    1977-01-01

    A small commercial SEM had been successfully shielded for examining radioactive materials transferred directly from a remote handling facility. Relatively minor mechanical modifications were required to achieve excellent operation. Two inches of steel provide adequate shielding for most samples encountered. However, samples reading 75 rad/hr γ have been examined by adding extra shielding in the form of tungsten sample holders and external lead shadow shields. Some degradation of secondary electron imaging was seen but was adequately compensated for by changing operating conditions

  6. Dose rate reduction using epoxy mixed lead shielding: experimental and theoretical determination of its shielding effectiveness

    International Nuclear Information System (INIS)

    Yadav, R.K.B.; Prasad, S.K.; Babu, K.S.; Hardiya, M.R.; Ullas, O.P.

    2010-01-01

    Full text: High background radiation field exists in Water Treatment Area (WTA) of Rod Cutting Building (RCB) in Cirus due to beta, gamma contamination on its floor. The high contamination on sides of wall and on floor is primarily due to deposition of activity generated during the regeneration of old mixed bed cartridges earlier (before year 1985) and presently due to deposition of contaminants by sump overflowing, wastes generated during maintenance/servicing of circulating pumps. RCB-WTA contribution to collective dose in present situation is up to 30% of the total collective dose of Cirus. Various options such as chipping of top layer of concrete floor of a sample area, in-situ placing of slab of cement and lead shot mixture were considered. In this case the man-rem consumption was high as radiation dose rate on concrete chip was 0.4 mGy/h and air activity generated was high, that too long lived with 137 Cs-as main constituent. The dose reduction factor was 1.7. In the second option the reduction in dose rate was insignificant and in-situ pouring of concrete consumed high collective dose. Hence above two options were not acceptable. Therefore the idea of tiling the contaminated floor with prefabricated epoxy mixed lead shots was accepted from ALARA point of view. It was concluded that pre-fabricated slabs of epoxy mixed lead slab of 25 mm thickness can be laid in RCB area to achieve a dose rate reduction factor of approximately five at a height of 30 cm above floor. This will result in a reduction of Person-mSv consumption in RCB by a factor of 5-10. These slabs of different thickness were fabricated outside RCB and were tested for shielding effectiveness experimentally by using radiation source and theoretically using MCNP code. Dose reduction factor of five for a point source, obtained experimentally for epoxy mixed lead shots was very near to value obtained by theoretical simulation. An extended calculation for an area source using this MCNP model gives a

  7. Studying the effect of nano lead compounds additives on the concrete shielding properties for γ-rays

    International Nuclear Information System (INIS)

    Hassan, H.E.; Badran, H.M.; Aydarous, A.; Sharshar, T.

    2015-01-01

    In the present work the effect of concrete incorporation with two types of nano-lead compounds on its γ-ray shielding characteristics is investigated. The concrete samples were prepared according to the local standards of building materials and doped by different percentages of PbO and PbTiO_3 nano powders which were prepared using co-precipitation and oxalate precursor techniques, respectively. In addition, commercial PbO_2 powder additive was used to check the effect of particle size on concrete attenuation properties. The phase composition and particle size of all the lead-oxide additives were confirmed by XRD and TEM imaging. The γ-rays attenuation coefficients were measured as a function of the additive percentage of lead compounds for γ-ray energies of 662, 1173 and 1332 keV using "1"3"7Cs and "6"0Co sources. The microstructure changes occurred in the concrete samples doped with Pb compounds additives were probed using the positron annihilation spectroscopy (PAS) and the results were compared with that for normal concrete. The obtained data revealed that the overall defect density of the investigated samples, as seen by the positrons, decreases with increasing the nano-PbO contents which is in agreement with the determined values of the samples apparent densities. It was found that the γ-ray attenuation coefficient of concrete doped by nano-PbO is improved. The results are explained in the view of the fine structure enhanced modification and its impact on the γ-ray interaction probability at different energies.

  8. Evaluation of eye shields made of tungsten and aluminum in high-energy electron beams

    International Nuclear Information System (INIS)

    Weaver, Randi D.; Gerbi, Bruce J.; Dusenbery, Kathryn E.

    1998-01-01

    Purpose: To protect the lens and cornea of the eye when treating the eyelid with electrons, we designed a tungsten and aluminum eye shield that protected both the lens and cornea, and also limited the amount of backscatter to the overlying eyelid when using electron beam therapy. Methods and Materials: Custom curved tungsten eye shields, 2 mm and 3 mm thick, were placed on Kodak XV film on 8 cm polystyrene and irradiated to evaluate the transmission through the shields. To simulate the thickness of the eyelid and to hold the micro-TLDs, an aquaplast mold was made to match the curvature of the eye shields. Backscatter was measured by placing the micro-TLDs on the beam entrance side to check the dose to the underside of the eyelid. Measurements were done with no aluminum, 0.5, and 1.0 mm of aluminum on top of the tungsten eye shields. The measurements were repeated with 2- and 3-mm flat pieces of lead to determine both the transmission and the backscatter dose for this material. Results: Tungsten proved to be superior to lead for shielding the underlying structures and for reducing backscatter. At 6 MeV, a 3-mm flat slab of tungsten plus 0.5 mm of aluminum, resulted in .042 Gy under the shield when 1.00 Gy is delivered to d max . At 6 MeV for a 3-mm lead plus 0.5-mm aluminum, .046 Gy was measured beneath the shield, a 9.5% decrease with the tungsten. Backscatter was also decreased from 1.17 to 1.13 Gy, a 4% decrease, when using tungsten plus 0.5 mm of aluminum vs. the same thickness of lead. Measurements using 9 MeV were performed in the same manner. With 3 mm tungsten and 0.5 mm of aluminum, at 3 mm depth the dose was .048 Gy compared to .079 Gy with lead and aluminum (39% decrease). Additionally, the backscatter dose was 3% less using tungsten. Simulating the lens dose 3 mm beyond the shield for the 2-mm and 3-mm custom curved tungsten eye shields plus 0.5 mm of aluminum was .030 and .024 Gy, respectively, using 6 MeV (20% decrease). Using 9-MeV electrons, the dose

  9. Evaluation of backscatter dose from internal lead shielding in clinical electron beams using EGSnrc Monte Carlo simulations.

    Science.gov (United States)

    De Vries, Rowen J; Marsh, Steven

    2015-11-08

    Internal lead shielding is utilized during superficial electron beam treatments of the head and neck, such as lip carcinoma. Methods for predicting backscattered dose include the use of empirical equations or performing physical measurements. The accuracy of these empirical equations required verification for the local electron beams. In this study, a Monte Carlo model of a Siemens Artiste linac was developed for 6, 9, 12, and 15 MeV electron beams using the EGSnrc MC package. The model was verified against physical measurements to an accuracy of better than 2% and 2mm. Multiple MC simulations of lead interfaces at different depths, corresponding to mean electron energies in the range of 0.2-14 MeV at the interfaces, were performed to calculate electron backscatter values. The simulated electron backscatter was compared with current empirical equations to ascertain their accuracy. The major finding was that the current set of backscatter equations does not accurately predict electron backscatter, particularly in the lower energies region. A new equation was derived which enables estimation of electron backscatter factor at any depth upstream from the interface for the local treatment machines. The derived equation agreed to within 1.5% of the MC simulated electron backscatter at the lead interface and upstream positions. Verification of the equation was performed by comparing to measurements of the electron backscatter factor using Gafchromic EBT2 film. These results show a mean value of 0.997 ± 0.022 to 1σ of the predicted values of electron backscatter. The new empirical equation presented can accurately estimate electron backscatter factor from lead shielding in the range of 0.2 to 14 MeV for the local linacs.

  10. BMFO-PVDF electrospun fiber based tunable metamaterial structures for electromagnetic interference shielding in microwave frequency region

    Science.gov (United States)

    Revathi, Venkatachalam; Dinesh Kumar, Sakthivel; Subramanian, Venkatachalam; Chellamuthu, Muthamizhchelvan

    2015-11-01

    Metamaterial structures are artificial structures that are useful in controlling the flow of electromagnetic radiation. In this paper, composite fibers of sub-micron thickness of barium substituted magnesium ferrite (Ba0.2Mg0.8Fe2O4) - polyvinylidene fluoride obtained by electrospinning is used as a substrate to design electromagnetic interference shielding structures. While electrospinning improves the ferroelectric properties of the polyvinylidene fluoride, the presence of barium magnesium ferrite modifies the magnetic property of the composite fiber. The dielectric and magnetic properties at microwave frequency measured using microwave cavity perturbation technique are used to design the reflection as well as absorption based tunable metamaterial structures for electromagnetic interference shielding in microwave frequency region. For one of the structures, the simulation indicates that single negative metamaterial structure becomes a double negative metamaterial under the external magnetic field.

  11. Impact of a flattening filter free linear accelerator on structural shielding design

    International Nuclear Information System (INIS)

    Jank, Julia; Kragl, Gabriele; Georg, Dietmar; Medical University of Vienna

    2014-01-01

    Purpose: The present study aimed to assess the effects of a flattening filter free medical accelerator on structural shielding demands of a treatment vault of a medical linear accelerator. We tried to answer the question, to what extent the required thickness of the shielding barriers can be reduced if instead of the standard flattened photon beams unflattened ones are used. Material and Methods: We chose both an experimental as well as a theoretical approach. On the one hand we measured photon dose rates at protected places outside the treatment room and compared the obtained results for flattened and unflattened beams. On the other hand we complied with international guidelines for adequate treatment vault design and calculated the shielding barriers according to the therein given specifications. Measurements were performed with an Elekta Precise trademark linac providing nominal photon energies of 6 and 10 MV. This machine underwent already earlier some modifications in order to be able to operate both with and without a flattening filter. Photon dose rates were measured with a LB133-1 dose rate meter manufactured by Berthold. To calculate the thickness of shielding barriers we referred to the Austrian standard OeNORM S 5216 and to the US American NCRP Report No. 151. Results: We determined a substantial photon dose rate reduction for all measurement points and photon energies. For unflattened 6 MV beams a reduction factor ranging from 1.4 to 1.8 was identified. The corresponding values for unflattened 10 MV beams were 2.1 and 3.2. The performed shielding calculations indicated the same tendency: For all relevant radiation components we found a reduction in shielding thickness when unflattened beams were used. The required thickness of primary barriers was reduced up to 8.0%, the thickness of secondary barriers up to 11.4%, respectively. Conclusions: For an adequate dimensioning of treatment vault shielding barriers it is by no means irrelevant if the

  12. Impact of a flattening filter free linear accelerator on structural shielding design.

    Science.gov (United States)

    Jank, Julia; Kragl, Gabriele; Georg, Dietmar

    2014-03-01

    The present study aimed to assess the effects of a flattening filter free medical accelerator on structural shielding demands of a treatment vault of a medical linear accelerator. We tried to answer the question, to what extent the required thickness of the shielding barriers can be reduced if instead of the standard flattened photon beams unflattened ones are used. We chose both an experimental as well as a theoretical approach. On the one hand we measured photon dose rates at protected places outside the treatment room and compared the obtained results for flattened and unflattened beams. On the other hand we complied with international guidelines for adequate treatment vault design and calculated the shielding barriers according to the therein given specifications. Measurements were performed with an Elekta Precise™ linac providing nominal photon energies of 6 and 10 MV. This machine underwent already earlier some modifications in order to be able to operate both with and without a flattening filter. Photon dose rates were measured with a LB133-1 dose rate meter manufactured by Berthold. To calculate the thickness of shielding barriers we referred to the Austrian standard ÖNORM S 5216 and to the US American NCRP Report No. 151. We determined a substantial photon dose rate reduction for all measurement points and photon energies. For unflattened 6 MV beams a reduction factor ranging from 1.4 to 1.8 was identified. The corresponding values for unflattened 10 MV beams were 2.1 and 3.2. The performed shielding calculations indicated the same tendency: For all relevant radiation components we found a reduction in shielding thickness when unflattened beams were used. The required thickness of primary barriers was reduced up to 8.0%, the thickness of secondary barriers up to 11.4%, respectively. For an adequate dimensioning of treatment vault shielding barriers it is by no means irrelevant if the accommodated linac operates with or without a flattening filter. The

  13. Impact of a flattening filter free linear accelerator on structural shielding design

    Energy Technology Data Exchange (ETDEWEB)

    Jank, Julia [Klinikum - Klagenfurt am Woerthersee (Austria). Inst. fuer Strahlentherapie und Radioonkologie; Kragl, Gabriele [Medical University of Vienna/AKH Vienna (Austria). Div. Medical Radiation Physics; Georg, Dietmar [Medical University of Vienna/AKH Vienna (Austria). Div. Medical Radiation Physics; Medical University of Vienna (Austria). Christian Doppler Lab. for Medical Radiation Research for Radiation Oncology

    2014-04-01

    Purpose: The present study aimed to assess the effects of a flattening filter free medical accelerator on structural shielding demands of a treatment vault of a medical linear accelerator. We tried to answer the question, to what extent the required thickness of the shielding barriers can be reduced if instead of the standard flattened photon beams unflattened ones are used. Material and Methods: We chose both an experimental as well as a theoretical approach. On the one hand we measured photon dose rates at protected places outside the treatment room and compared the obtained results for flattened and unflattened beams. On the other hand we complied with international guidelines for adequate treatment vault design and calculated the shielding barriers according to the therein given specifications. Measurements were performed with an Elekta Precise trademark linac providing nominal photon energies of 6 and 10 MV. This machine underwent already earlier some modifications in order to be able to operate both with and without a flattening filter. Photon dose rates were measured with a LB133-1 dose rate meter manufactured by Berthold. To calculate the thickness of shielding barriers we referred to the Austrian standard OeNORM S 5216 and to the US American NCRP Report No. 151. Results: We determined a substantial photon dose rate reduction for all measurement points and photon energies. For unflattened 6 MV beams a reduction factor ranging from 1.4 to 1.8 was identified. The corresponding values for unflattened 10 MV beams were 2.1 and 3.2. The performed shielding calculations indicated the same tendency: For all relevant radiation components we found a reduction in shielding thickness when unflattened beams were used. The required thickness of primary barriers was reduced up to 8.0%, the thickness of secondary barriers up to 11.4%, respectively. Conclusions: For an adequate dimensioning of treatment vault shielding barriers it is by no means irrelevant if the

  14. Cooling Performance of TBM-shield Designed for Manufacturability

    International Nuclear Information System (INIS)

    Park, Seong Dae; Lee, Dong Won; Kim, Dong Jun; Yoon, Jae Sung; Ahn, Mu Young

    2016-01-01

    Helium cooled ceramic reflector (HCCR) test blanket module (TBM) is composed of four sub-modules and a common back manifold (BM). The associated shield is a water-cooled 316L(N)-IG block with internal cooling channels. The purpose of the TBM-shield is to make the condition with the allowable neutron flux and dose rate level. The radially continuous layers of water and structure were configured. The main purpose of the shield is to reduce the neutron flux by absorbing the neutron in the structure. The water could act as the moderator and cool down the structure which is heated due to the reaction with the neutrons. The moderated neutrons are easily absorbed by the structure. It could meet the criteria for the minimum neutron flux by increasing the thickness of structure. The formation of inside cooling channel in the TBM-shield should be considered while maintaining the allowable temperature range. In this work, a manufacturing process including the formation of inside cooling channel was presented. Current design and thermal analysis results for the TBM-shield were presented. The geometry of the shield blocks was considerably changed. The coolant channel was exposed to the outer surface of the TBM-shield. The overall manufacturing process is simplified compared with the previous process of CD model

  15. Cooling Performance of TBM-shield Designed for Manufacturability

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seong Dae; Lee, Dong Won; Kim, Dong Jun; Yoon, Jae Sung [KAERI, Daejeon (Korea, Republic of); Ahn, Mu Young [NFRI, Daejeon (Korea, Republic of)

    2016-05-15

    Helium cooled ceramic reflector (HCCR) test blanket module (TBM) is composed of four sub-modules and a common back manifold (BM). The associated shield is a water-cooled 316L(N)-IG block with internal cooling channels. The purpose of the TBM-shield is to make the condition with the allowable neutron flux and dose rate level. The radially continuous layers of water and structure were configured. The main purpose of the shield is to reduce the neutron flux by absorbing the neutron in the structure. The water could act as the moderator and cool down the structure which is heated due to the reaction with the neutrons. The moderated neutrons are easily absorbed by the structure. It could meet the criteria for the minimum neutron flux by increasing the thickness of structure. The formation of inside cooling channel in the TBM-shield should be considered while maintaining the allowable temperature range. In this work, a manufacturing process including the formation of inside cooling channel was presented. Current design and thermal analysis results for the TBM-shield were presented. The geometry of the shield blocks was considerably changed. The coolant channel was exposed to the outer surface of the TBM-shield. The overall manufacturing process is simplified compared with the previous process of CD model.

  16. Development and production of radiation shielding window (RSW) glass: Indian scenario

    International Nuclear Information System (INIS)

    Phani, K.K.

    2006-01-01

    Nuclear energy/power and its peaceful applications play an ever increasing role in India. Irradiated nuclear fuels, irradiated structural materials from reactors, nuclear wastes and radio-isotopes emit high energy gamma radiations which are extremely health hazardous. These materials are handled remotely by manipulators inside the hot cells, which are constructed by shielding materials such as lead and concrete walls. The direct visual control of processes in the hot cells during operation demands the windows in the radiation shielding walls. These windows must provide the clear viewing but yet ensure the good protection to the working personnel from the high energy radiation

  17. Radiation-shielding transparent material

    International Nuclear Information System (INIS)

    Kusumeki, Asao.

    1983-01-01

    Purpose : To obtain radiation-shielding transparent material having a high resistivity to the radioactive rays or light irradiation which is greater at least by two digits as compared with lead glass. Constitution : The shielding material is composed of a saturated aqueous solution zinc iodide. Zinc iodide (specific gravity of 4.2) is dissolved by 430 g into 100 cc of water at a temperature of 20 0 C and forms a heavy liquid with a specific gravity of 2.80. The radiation length of the heavy liquid is 3.8 cm which is 1.5 times as large as lead glass. The light transmission is greater than 95% in average. Furthermore, by adding hypophosphorous acid as a reducing agent to the aqueous solution of the lead iodide, the material is stabilized against the irradiation of light or radioactive rays and causes no discoloration for a long time. (Moriyama, K.)

  18. Integrated evaluation of the geology, aerogammaspectrometry and aeromagnetometry of the Sul-Riograndense Shield, southernmost Brazil.

    Science.gov (United States)

    Hartmann, Léo A; Lopes, William R; Savian, Jairo F

    2016-03-01

    An integrated evaluation of geology, aerogammaspectrometry and aeromagnetometry of the Sul-Riogran-dense Shield is permitted by the advanced stage of understanding of the geology and geochronology of the southern Brazilian Shield and a 2010 airborne geophysical survey. Gamma rays are registered from the rocks near the surface and thus describe the distribution of major units in the shield, such as the Pelotas batholith, the juvenile São Gabriel terrane, the granulite-amphibolite facies Taquarembó terrane and the numerous granite intrusions in the foreland. Major structures are also observed, e.g., the Dorsal de Canguçu shear. Magnetic signals register near surface crustal compositions (analytic signal) and total crust composition (total magnetic signal), so their variation as measured indicates either shallow or whole crustal structures. The Caçapava shear is outstanding on the images as is the magnetic low along the N-S central portion of the shield. These integrated observations lead to the deepening of the understanding of the largest and even detailed structures of the Sul-Riograndense Shield, some to be correlated to field geology in future studies. Most significant is the presence of different provinces and their limits depending on the method used for data acquisition - geology, aerogammaspectrometry or aeromagnetometry.

  19. Effect of molybdenum on gamma ray shielding and structural properties of PbO-B2O3 glasses

    Science.gov (United States)

    Dogra, Mridula; Singh, K. J.; Kaur, Kulwinder

    2018-04-01

    The present study is aimed at developing new shielding materials for gamma ray shielding applications. Transparent glasses of the composition xMoO3-0.7PbO-(0.3-x)B2O3 where x= 0.03 to 0. 06 (mole fraction) have been prepared by using melt-quenchingtechnique. Gamma ray shielding properties have been evaluated in terms of mass attenuation coefficient and half value layer parameter at photon energies 662 and 1173 keV. These shielding parameters are also compared with standard shielding material`concretes'. It has been found that prepared glass system shows better shielding properties than barite and ordinary concretes proving the possibility of its usage as an alternate to conventional concrete for gamma ray shielding applications. The density, molar volume, X-Ray Diffraction, Fourier Transform InfraRed and Raman studies have been performed to study the structural properties of the glass system. It has been analyzed from FTIR and Raman studies that bridging oxygens increase with the decrease of MoO3 content in the glass composition.

  20. X-ray shielding behaviour of kaolin derived mullite-barites ceramic

    Science.gov (United States)

    Ripin, A.; Mohamed, F.; Choo, T. F.; Yusof, M. R.; Hashim, S.; Ghoshal, S. K.

    2018-03-01

    Mullite-barite ceramic (MBC) is an emergent material for effective shielding of redundant ionizing radiation exposure. The composition dependent mechanical, thermal, and microstructure properties of MBC that makes MBC a high performing novel radiation shielding candidate remained unexplored. This paper examines the possibility of exploiting Malaysian kaolin (AKIM-35) and barite (BaSO4) derived ceramic (MBC) system for X-ray shielding operation. Using conventional pressing and sintering method six ceramic samples are prepared by mixing AKIM-35 with barite at varying contents (0, 10, 20, 30, 40 and 50 wt%). Synthesized pressed mixtures are calcined at 400 °C for 30 min and then sintered to 1300 °C for 120 min at a heating rate of 10 °C/min. Sintered samples are characterized via X-ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), lead equivalent (LE), uniformity and dose reduction analyses. XRD pattern of prepared ceramics revealed the presence of monoclinic barium alumino-silicate (BAS) and orthorhombic mullite as major shielding phases together with other minor phase of barite and hexagonal quartz (SiO2) structures. Furthermore, FESEM images of ceramics (between 0 and 30 wt%) displayed the existence of compacted monoclinic plate of BAS and acicular mullite morphology (ceramics at 40 and 50 wt%). Radiation tests displayed the capacity of ceramics (at 0 and 10 wt%) to shield the X-ray radiation emanated at tube potential range of 50-120 kV. The highest radiation attenuation is ascertained at 70 kV where the dose is reduced remarkably between 99.11% and 97.42%. Ceramics at 0 and 10 wt% demonstrated the highest lead (Pb) equivalent thickness (LE) of 0.44 mm and 0.34 mm, respectively. It is established that such MBC may contribute towards the development of shielding material against ionizing radiation in diagnostic radiology (X-ray) dose range.

  1. Decontamination and coating of lead

    International Nuclear Information System (INIS)

    Rankin, W.N.; Bush, S.P.; Lyon, C.E.; Walker, V.

    1988-01-01

    Technology is being developed to decontaminate lead used in shielding applications in contaminated environments for recycle as shieldings. Technology is also being developed to coat either decontaminated lead or new lead before it is used in contaminated environments. The surface of the coating is expected to be much easier to decontaminate than the original lead surface. If contamination becomes severely embedded in the coating and cannot be removed, it can be easily cut with a knife and removed from the lead. The used coating can be disposed of as radioactive (hot hazardous) waste. The lead can then be recoated for further use as a shielding material

  2. A study on the effect of crack in concrete structure in the point of radiation shielding

    International Nuclear Information System (INIS)

    Lee, Chang-Min; Lee, Yoon-Hee; Lee, Kun-Jai; Cho, Cheon-Hyung; Choi, Byung-Il; Lee, Heung-Young

    2005-01-01

    The saturation of South Korea's at-reactor (AR) spent fuel storage pools has created a necessity for additional spent fuel storage capacity. Because the South Korean government has a plan to increase the number of nuclear power plants to 27 units by 2016, the increase of spent nuclear fuel generation will be accelerated. Because there is no concrete plan for spent unclear fuel permanent disposal, the Korea hydraulic nuclear power company is planning to construct dry storage facility. Spent nuclear fuel from CANDU type nuclear power plant will be stored in MACSTOR-400 composed by reinforced concrete. Because it is new model, it has to be licensed. Life time estimation is needed for licensing. Deterioration of reinforced concrete structure is currently of great concern for life time estimation. The most significant form of deterioration is reinforcement corrosion that gives rise to crack the concrete structure. In this study, in order to estimate the life time of MACSTOR, the tendency of crack creation, propagation and the effect of crack in concrete structure against radiation shielding are investigated. Crack creation and propagation depends on concrete cover thickness and c/d ratio. The surface dose rate at the concrete shield in MACSTOR is simulated by MCNP code about several cases. Generally in the case of point source, surface dose rate depends on shape, width and length of crack. In the case of MACSTOR-400, It is estimated that crack is not dominant factor in the point of radiation shielding in less than 0.4mm of crack width. Above results will be helpful to estimate the life time of concrete structure as radiation shield

  3. Evaluation of rubber composites as shielding materials against ionizing radiation

    International Nuclear Information System (INIS)

    Atia, M.K.

    2010-01-01

    Styrene-butadiene rubber/lead oxide composites were prepared as γ-radiation shields.The composites were prepared with different concentration of red lead oxide (Pb 3 O 4 ) .The assessment of the linear attenuation coefficient of the SBR/lead oxide composites for γ -rays from 137 Cs 137 γ-radiation point source was studied . The factors affecting the mechanical properties and shielding capacity of the composites were also studied. These factors include the lead oxide concentration, the type of monomers added and the irradiation dose. The styrene-butadiene rubber/lead oxide composites can attain up to about 43% of the shielding capacity of pure lead. The incorporation of high concentrations of lead oxide and the effect of accumulative irradiation doses up to 3000 kGy on the physico-mechanical properties of the composites were studied . These led to hardening of the SBR rubber/lead oxide composites.

  4. Superconductor shields test chamber from ambient magnetic fields

    Science.gov (United States)

    Hildebrandt, A. F.

    1965-01-01

    Shielding a test chamber for magnetic components enables it to maintain a constant, low magnetic field. The chamber is shielded from ambient magnetic fields by a lead foil cylinder maintained in a superconducting state by liquid helium.

  5. Corrosion of lead shielding in a radiology department

    International Nuclear Information System (INIS)

    Schick, D.K.; CAsey, R.N.; Sim, L.H.; Siddle, K.J.

    1999-01-01

    Corrosion of lead sheet used for structural radiation protection in the Princess Alexandra Hospital Radiology Department has been identified. The corrosion is thought to have been caused by organic acid vapours released from oregon timber wall panelling. Non-destructive testing (NDT) and X-ray transmission measurements were used to define the extent and severity of damage, and subsequently to provide the data necessary for estimation of staff and public radiation doses. Although radiation dose limits have not been exceeded, corrective actions including structural modifications and staff information sessions have been undertaken. Copyright (1999) Blackwell Science Pty Ltd

  6. Adaptive planning using megavoltage fan-beam CT for radiation therapy with testicular shielding

    International Nuclear Information System (INIS)

    Yadav, Poonam; Kozak, Kevin; Tolakanahalli, Ranjini; Ramasubramanian, V.; Paliwal, Bhudatt R.; Welsh, James S.; Rong, Yi

    2012-01-01

    This study highlights the use of adaptive planning to accommodate testicular shielding in helical tomotherapy for malignancies of the proximal thigh. Two cases of young men with large soft tissue sarcomas of the proximal thigh are presented. After multidisciplinary evaluation, preoperative radiation therapy was recommended. Both patients were referred for sperm banking and lead shields were used to minimize testicular dose during radiation therapy. To minimize imaging artifacts, kilovoltage CT (kVCT) treatment planning was conducted without shielding. Generous hypothetical contours were generated on each “planning scan” to estimate the location of the lead shield and generate a directionally blocked helical tomotherapy plan. To ensure the accuracy of each plan, megavoltage fan-beam CT (MVCT) scans were obtained at the first treatment and adaptive planning was performed to account for lead shield placement. Two important regions of interest in these cases were femurs and femoral heads. During adaptive planning for the first patient, it was observed that the virtual lead shield contour on kVCT planning images was significantly larger than the actual lead shield used for treatment. However, for the second patient, it was noted that the size of the virtual lead shield contoured on the kVCT image was significantly smaller than the actual shield size. Thus, new adaptive plans based on MVCT images were generated and used for treatment. The planning target volume was underdosed up to 2% and had higher maximum doses without adaptive planning. In conclusion, the treatment of the upper thigh, particularly in young men, presents several clinical challenges, including preservation of gonadal function. In such circumstances, adaptive planning using MVCT can ensure accurate dose delivery even in the presence of high-density testicular shields.

  7. Adaptive planning using megavoltage fan-beam CT for radiation therapy with testicular shielding

    Science.gov (United States)

    Yadav, Poonam; Kozak, Kevin; Tolakanahalli, Ranjini; Ramasubramanian, V.; Paliwal, Bhudatt R.; Welsh, James S.; Rong, Yi

    2012-01-01

    This study highlights the use of adaptive planning to accommodate testicular shielding in helical tomotherapy for malignancies of the proximal thigh. Two cases of young men with large soft tissue sarcomas of the proximal thigh are presented. After multidisciplinary evaluation, preoperative radiation therapy was recommended. Both patients were referred for sperm banking and lead shields were used to minimize testicular dose during radiation therapy. To minimize imaging artifacts, kilovoltage CT (kVCT) treatment planning was conducted without shielding. Generous hypothetical contours were generated on each “planning scan” to estimate the location of the lead shield and generate a directionally blocked helical tomotherapy plan. To ensure the accuracy of each plan, megavoltage fan-beam CT (MVCT) scans were obtained at the first treatment and adaptive planning was performed to account for lead shield placement. Two important regions of interest in these cases were femurs and femoral heads. During adaptive planning for the first patient, it was observed that the virtual lead shield contour on kVCT planning images was significantly larger than the actual lead shield used for treatment. However, for the second patient, it was noted that the size of the virtual lead shield contoured on the kVCT image was significantly smaller than the actual shield size. Thus, new adaptive plans based on MVCT images were generated and used for treatment. The planning target volume was underdosed up to 2% and had higher maximum doses without adaptive planning. In conclusion, the treatment of the upper thigh, particularly in young men, presents several clinical challenges, including preservation of gonadal function. In such circumstances, adaptive planning using MVCT can ensure accurate dose delivery even in the presence of high-density testicular shields. PMID:21925866

  8. Adaptive planning using megavoltage fan-beam CT for radiation therapy with testicular shielding

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Poonam [Department of Human Oncology, University of Wisconsin, Madison, Madison, WI (United States); Department of Medical Physics, University of Wisconsin, Madison, Madison, WI (United States); School of Advance Sciences, Vellore Institue of Technology University, Vellore, Tamil Nadu (India); Kozak, Kevin [Department of Human Oncology, University of Wisconsin, Madison, Madison, WI (United States); Tolakanahalli, Ranjini [Department of Human Oncology, University of Wisconsin, Madison, Madison, WI (United States); Department of Medical Physics, University of Wisconsin, Madison, Madison, WI (United States); Ramasubramanian, V. [School of Advance Sciences, Vellore Institue of Technology University, Vellore, Tamil Nadu (India); Paliwal, Bhudatt R. [Department of Human Oncology, University of Wisconsin, Madison, Madison, WI (United States); Department of Medical Physics, University of Wisconsin, Madison, Madison, WI (United States); University of Wisconsin, Riverview Cancer Centre, Wisconsin Rapids, WI (United States); Welsh, James S. [Department of Human Oncology, University of Wisconsin, Madison, Madison, WI (United States); Department of Medical Physics, University of Wisconsin, Madison, Madison, WI (United States); Rong, Yi, E-mail: rong@humonc.wisc.edu [Department of Human Oncology, University of Wisconsin, Madison, Madison, WI (United States); University of Wisconsin, Riverview Cancer Centre, Wisconsin Rapids, WI (United States)

    2012-07-01

    This study highlights the use of adaptive planning to accommodate testicular shielding in helical tomotherapy for malignancies of the proximal thigh. Two cases of young men with large soft tissue sarcomas of the proximal thigh are presented. After multidisciplinary evaluation, preoperative radiation therapy was recommended. Both patients were referred for sperm banking and lead shields were used to minimize testicular dose during radiation therapy. To minimize imaging artifacts, kilovoltage CT (kVCT) treatment planning was conducted without shielding. Generous hypothetical contours were generated on each 'planning scan' to estimate the location of the lead shield and generate a directionally blocked helical tomotherapy plan. To ensure the accuracy of each plan, megavoltage fan-beam CT (MVCT) scans were obtained at the first treatment and adaptive planning was performed to account for lead shield placement. Two important regions of interest in these cases were femurs and femoral heads. During adaptive planning for the first patient, it was observed that the virtual lead shield contour on kVCT planning images was significantly larger than the actual lead shield used for treatment. However, for the second patient, it was noted that the size of the virtual lead shield contoured on the kVCT image was significantly smaller than the actual shield size. Thus, new adaptive plans based on MVCT images were generated and used for treatment. The planning target volume was underdosed up to 2% and had higher maximum doses without adaptive planning. In conclusion, the treatment of the upper thigh, particularly in young men, presents several clinical challenges, including preservation of gonadal function. In such circumstances, adaptive planning using MVCT can ensure accurate dose delivery even in the presence of high-density testicular shields.

  9. Superhydrophilic poly (styrene co acrylonitrile)-ZnO nanocomposite surfaces for UV shielding and self-cleaning applications

    Science.gov (United States)

    Singh, Rajender; Sharma, Ramesh; Barman, P. B.; Sharma, Dheeraj

    2017-11-01

    UV shielding based super hydrophilic material is developed in the present formulation by in situ emulsion polymerization of poly (styrene-acrylonitrile) with ZnO nanoparticles. The ESI-MS technique confirms the structure of polymer nanocomposite by their mass fragments. The XRD study confirms the presence of ZnO phase in polymer matrix. PSAN/ZnO nanocomposite leads to give effective UV shielding (upto 375 nm) and visible luminescence with ZnO content in polymer matrix. The FESEM and TEM studies confirm the symmetrical, controlled growth of PNs. The incorporation of ZnO nanofillers into PSAN matrix lead to restructuring the PNs surfaces into superhydrophilic surfaces in water contact angle (WCA) from 70° to 10°. We believe our synthesized PSAN/ZnO nanocomposite could be potential as UV shielding, luminescent and super hydrophilic nature based materials in related commercial applications.

  10. Efficacy of Lower-Body Shielding in Computed Tomography Fluoroscopy-Guided Interventions

    International Nuclear Information System (INIS)

    Mahnken, Andreas H.; Sedlmair, Martin; Ritter, Christine; Banckwitz, Rosemarie; Flohr, Thomas

    2012-01-01

    Purpose: Computed tomography (CT) fluoroscopy-guided interventions pose relevant radiation exposure to the interventionalist. The goal of this study was to analyze the efficacy of lower-body shielding as a simple structural method for decreasing radiation dose to the interventionalist without limiting access to the patient. Material and Methods: All examinations were performed with a 128-slice dual source CT scanner (12 × 1.2-mm collimation; 120 kV; and 20, 40, 60, and 80 mAs) and an Alderson-Rando phantom. Scatter radiation was measured with an ionization chamber and a digital dosimeter at standardized positions and heights with and without a lower-body lead shield (0.5-mm lead equivalent; Kenex, Harlow, UK). Dose decreases were computed for the different points of measurement. Results: On average, lower-body shielding decreased scatter radiation by 38.2% within a 150-cm radius around the shielding. This decrease is most significant close to the gantry opening and at low heights of 50 and 100 cm above the floor with a maximum decrease of scatter radiation of 95.9% close to the scanner’s isocentre. With increasing distance to the gantry opening, the effect decreased. There is almost no dose decrease effect at ≥150 above the floor. Scatter radiation and its decrease were linearly correlated with the tube current-time product (r 2 = 0.99), whereas percent scatter radiation decrease was independent of the tube current-time product. Conclusion: Lower-body shielding is an effective way to decrease radiation exposure to the interventionalist and should routinely be used in CT fluoroscopy-guided interventions.

  11. Collection shield for ion separation apparatus

    International Nuclear Information System (INIS)

    Ford, K.L.; Pugh, R.A.

    1981-01-01

    The ion separation electrodes in isotope separation apparatus are provided with removable collection shields to collect neutral particles which would normally pass through the ionization region. A preferred collection shield comprises a u-shaped section for clipping onto the leading edge of an electrode and a pair of flanges projecting substantially perpendicular to the clipping section for collecting neutral particles

  12. Concrete radiation shielding

    International Nuclear Information System (INIS)

    Kaplan, M.F.

    1989-01-01

    The increased use of nuclear energy has given rise to a growth in the amount of artificially produced radiation and radioactive materials. The design and construction of shielding to protect people, equipment and structures from the effects of radiation has never been more important. Experience has shown that concrete is an effective, versatile and economical material for the construction of radiation shielding. This book provides information on the principles governing the interaction of radiation with matter and on relevant nuclear physics to give the engineer an understanding of the design and construction of concrete shielding. It covers the physical, mechanical and nuclear properties of concrete; the effects of elevated temperatures and possible damage to concrete due to radiation; basic procedures for the design of concrete radiation shields and finally the special problems associated with their construction and cost. Although written primarily for engineers concerned with the design and construction of concrete shielding, the book also reviews the widely scattered data and information available on this subject and should therefore be of interest to students and those wishing to research further in this field. (author)

  13. The Fabrication of Internal Shielding using Provil and Cerrobend

    International Nuclear Information System (INIS)

    Kim Jong Hwa; Lee, Kang Hyun; Son, Jeong Hye

    1996-01-01

    The skin cancer is a highly curable disease which frequently occurs in the head and neck region exposed to the sun. When the eyelid is treated usually eye shield made of lead is used to protect the eyeball as a internal shield. For the same reason on internal shield should be used when the nose is treated when electron to protect the nasal mucosa. Our hospital made an internal shield for the treatment of the skin cancer on the nose using provil and cerrobend. The characteristics of the internal shield were examined.

  14. An Evaluation on Radiation Shielding and Activation Properties of ISOL-bunker Structural Materials for Radiation Safety in RAON Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Do Hyun; Kim, Song Hyun; Woo, Myeong Hyeon; Lee, Jae Yong; Kim, Jong Woo; Shin, Chang Ho [Hanyang University, Seoul (Korea, Republic of); Nam, Shin Woo [Institute for Basic Science, Daejeon (Korea, Republic of)

    2015-10-15

    RAON heavy ion accelerator has been designed by the Institute for Basic Science (IBS). ISOL is one of RAON facilities to generate and separate rare isotopes. For generating rare isotopes, high intensity proton beam, which has 70 MeV energy, is induced into UCx target. From this reaction, lots of neutrons are concomitantly generated. To meet our design goal, it was required that the structural material of ISOL-bunker should be carefully selected. In this study, to select the structural material which has lower activation property with higher performance for radiation shielding, following aspects were evaluated: (i) residual dose, (ii) radioactive wastes, and (iii) shielding performance in ISOL-bunker. In this study, to effectively design the radiation shielding of the RAON ISOL-bunker, two methods were proposed. No.1 strategy is a method to replace the normal concrete to specific concretes. No.2 strategy is to design dual-layer radiation shields that a specific shielding material is located inner side of the normal concrete. Using the strategies, performance evaluations were evaluated for three aspects, which are residual dose, radioactive waste, and prompt radiation. The results show that the residual radiation can be effectively reduced using B{sub 4}C, borated polyethylene and polyethylene with No.2 strategy. Also, the colemanite concrete and B{sub 4}C shielding give a good ability to reduce the radioactive wastes.

  15. RADSHI: shielding calculation program for different geometries sources

    International Nuclear Information System (INIS)

    Gelen, A.; Alvarez, I.; Lopez, H.; Manso, M.

    1996-01-01

    A computer code written in pascal language for IBM/Pc is described. The program calculates the optimum thickness of slab shield for different geometries sources. The Point Kernel Method is employed, which enables the obtention of the ionizing radiation flux density. The calculation takes into account the possibility of self-absorption in the source. The air kerma rate for gamma radiation is determined, and with the concept of attenuation length through the equivalent attenuation length the shield is obtained. The scattering and the exponential attenuation inside the shield material is considered in the program. The shield materials can be: concrete, water, iron or lead. It also calculates the shield for point isotropic neutron source, using as shield materials paraffin, concrete or water. (authors). 13 refs

  16. Design of Reflective, Photonic Shields for Atmospheric Reentry

    Science.gov (United States)

    Komarevskiy, Nikolay; Shklover, Valery; Braginsky, Leonid; Hafner, Christian; Fabrichnaya, Olga; White, Susan; Lawson, John

    2010-01-01

    We present the design of one-dimensional photonic crystal structures, which can be used as omnidirectional reflecting shields against radiative heating of space vehicles entering the Earth's atmosphere. This radiation is approximated by two broad bands centered at visible and near-infrared energies. We applied two approaches to find structures with the best omnidirectional reflecting performance. The first approach is based on a band gap analysis and leads to structures composed of stacked Bragg mirrors. In the second approach, we optimize the structure using an evolutionary strategy. The suggested structures are compared with a simple design of two stacked Bragg mirrors. Choice of the constituent materials for the layers as well as the influence of interlayer diffusion at high temperatures are discussed.

  17. ITER shielding blanket

    Energy Technology Data Exchange (ETDEWEB)

    Strebkov, Yu [ENTEK, Moscow (Russian Federation); Avsjannikov, A [ENTEK, Moscow (Russian Federation); Baryshev, M [NIAT, Moscow (Russian Federation); Blinov, Yu [ENTEK, Moscow (Russian Federation); Shatalov, G [KIAE, Moscow (Russian Federation); Vasiliev, N [KIAE, Moscow (Russian Federation); Vinnikov, A [ENTEK, Moscow (Russian Federation); Chernjagin, A [DYNAMICA, Moscow (Russian Federation)

    1995-03-01

    A reference non-breeding blanket is under development now for the ITER Basic Performance Phase for the purpose of high reliability during the first stage of ITER operation. More severe operation modes are expected in this stage with first wall (FW) local heat loads up to 100-300Wcm{sup -2}. Integration of a blanket design with protective and start limiters requires new solutions to achieve high reliability, and possible use of beryllium as a protective material leads to technologies. The rigid shielding blanket concept was developed in Russia to satisfy the above-mentioned requirements. The concept is based on a copper alloy FW, austenitic stainless steel blanket structure, water cooling. Beryllium protection is integrated in the FW design. Fabrication technology and assembly procedure are described in parallel with the equipment used. (orig.).

  18. Effect of compositional variation in plutonium on process shielding design

    Energy Technology Data Exchange (ETDEWEB)

    Brown, T.H.

    1997-11-01

    Radiation dose rate from plutonium with high {sup 239}Pu content varies with initial nuclidic content, radioactive decay time, and impurity elemental content. The two idealized states of old plutonium and clean plutonium, whose initial compositions are given, provide approximate upper and lower bounds on dose rate variation. Whole-body dose rates were calculated for the two composition states, using unshielded and shielded plutonium spheres of varying density. The dose rates from these variable density spheres are similar to those from expanded plutonium configurations encountered during processing. The dose location of 40 cm from the sphere center is representative of operator standoff for direct handling of plutonium inside a glove box. The results have shielding implications for glove boxes with only structurally inherent shielding, especially for processing of old plutonium in an expanded configuration. Further reduction in total dose rate by using lead to reduce photon dose rate is shown for two density cases representing compact and expanded plutonium configurations.

  19. Effect of compositional variation in plutonium on process shielding design

    International Nuclear Information System (INIS)

    Brown, T.H.

    1997-11-01

    Radiation dose rate from plutonium with high 239 Pu content varies with initial nuclidic content, radioactive decay time, and impurity elemental content. The two idealized states of old plutonium and clean plutonium, whose initial compositions are given, provide approximate upper and lower bounds on dose rate variation. Whole-body dose rates were calculated for the two composition states, using unshielded and shielded plutonium spheres of varying density. The dose rates from these variable density spheres are similar to those from expanded plutonium configurations encountered during processing. The dose location of 40 cm from the sphere center is representative of operator standoff for direct handling of plutonium inside a glove box. The results have shielding implications for glove boxes with only structurally inherent shielding, especially for processing of old plutonium in an expanded configuration. Further reduction in total dose rate by using lead to reduce photon dose rate is shown for two density cases representing compact and expanded plutonium configurations

  20. Using thin metal layers on composite structures for shielding the electromagnetic pulse caused by nearby lightning

    NARCIS (Netherlands)

    Blaj, M.A.; Buesink, Frederik Johannes Karel; Damstra, G.C.; Leferink, Frank Bernardus Johannes

    2011-01-01

    Electronic systems in composite structures could be vulnerable to the (dominant magnetic) field caused by a lightning strike, because only thin layers of metal can be used on composite structures. Thin layers result in a very low shielding effectiveness against magnetic fields. Many experiments

  1. MOSFET Dosimetry for Evaluation of Gonad Shielding during Radiotherapy

    International Nuclear Information System (INIS)

    Kim, Hwi Young; Choi, Yun Seok; Park, So Yeon; Park, Yang Kyun; Ye, Sung Joon

    2011-01-01

    In order to confirm feasibility of MOSFET modality in use of in vivo dosimetry, evaluation of gonad shielding in order to minimize gonadal dose of patients undergoing radiotherapy by using MOSFET modality was performed. Gonadal dose of patients undergoing radiotherapy for rectal cancer in the department of radiation oncology of Seoul National University Hospital since 2009 was measured. 6 MV and 15 MV photon beams emitted from Varian 21EX LINAC were used for radiotherapy. In order to minimize exposed dose caused by the scattered ray not only from collimator of LINAC but also from treatment region inside radiation field, we used box.shaped lead shielding material. The shielding material was made of the lead block and consists of 7.5 cm x 9.5 cm x 5.5 cm sized case and 9 cm x 9.5 cm x 1 cm sized cover. Dosimetry for evaluation of gonad shielding was done with MOSFET modality. By protecting with gonad shielding material, average gonadal dose of patients was decreased by 23.07% compared with reference dose outside of the shielding material. Average delivered gonadal dose inside the shielding material was 0.01 Gy. By the result of MOSFET dosimetry, we verified that gonadal dose was decreased by using gonad shielding material. In compare with TLD dosimetry, we could measure the exposed dose easily and precisely with MOSFET modality

  2. MOSFET Dosimetry for Evaluation of Gonad Shielding during Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hwi Young; Choi, Yun Seok; Park, So Yeon; Park, Yang Kyun [Seoul National University College of Medicine, Seoul (Korea, Republic of); Ye, Sung Joon [Seoul National University, Seoul (Korea, Republic of)

    2011-03-15

    In order to confirm feasibility of MOSFET modality in use of in vivo dosimetry, evaluation of gonad shielding in order to minimize gonadal dose of patients undergoing radiotherapy by using MOSFET modality was performed. Gonadal dose of patients undergoing radiotherapy for rectal cancer in the department of radiation oncology of Seoul National University Hospital since 2009 was measured. 6 MV and 15 MV photon beams emitted from Varian 21EX LINAC were used for radiotherapy. In order to minimize exposed dose caused by the scattered ray not only from collimator of LINAC but also from treatment region inside radiation field, we used box.shaped lead shielding material. The shielding material was made of the lead block and consists of 7.5 cm x 9.5 cm x 5.5 cm sized case and 9 cm x 9.5 cm x 1 cm sized cover. Dosimetry for evaluation of gonad shielding was done with MOSFET modality. By protecting with gonad shielding material, average gonadal dose of patients was decreased by 23.07% compared with reference dose outside of the shielding material. Average delivered gonadal dose inside the shielding material was 0.01 Gy. By the result of MOSFET dosimetry, we verified that gonadal dose was decreased by using gonad shielding material. In compare with TLD dosimetry, we could measure the exposed dose easily and precisely with MOSFET modality.

  3. Detailed mechanical design of the LIPAc beam dump radiological shielding

    Energy Technology Data Exchange (ETDEWEB)

    Nomen, Oriol, E-mail: onomen@irec.cat [IREC, Barcelona, Catalonia (Spain); CDEI-UPC, Barcelona, Catalonia (Spain); Martínez, José I.; Arranz, Fernando; Iglesias, Daniel; Barrera, Germán; Brañas, Beatriz [CIEMAT, Madrid (Spain); Ogando, Francisco [UNED, Madrid (Spain); Molla, Joaquín [CIEMAT, Madrid (Spain); Sanmartí, Manel [IREC, Barcelona, Catalonia (Spain)

    2013-10-15

    Highlights: ► Mechanical design of the IFMIF LIPAc beam dump shielding has been performed. ► Lead shutter design performed to shield radiation from beam dump when LIPAc is off. ► External loads, working and dismantling conditions, included as design constraints. -- Abstract: The LIPAc is a 9 MeV, D{sup +} linear prototype accelerator for the validation of the IFMIF accelerator design. The high intensity, 125 mA CW beam is stopped in a copper cone involving a high production of neutrons and gamma radiation and activation of its surface. The beam stopper is surrounded by a shielding to attenuate the resulting radiation so that dose rate values comply with the limits at the different zones of the installation. The shielding includes for that purpose polyethylene rings, water tanks and gray cast iron rings. A lead shutter has also been designed to shield the gamma radiation that comes through the beam tube when the linear accelerator is not in operation, in order to allow access inside the building for maintenance tasks. The present work summarizes the detailed mechanical design of the beam dump shielding and the lead shutter taking into account the design constraints, such as working conditions and other external loads, as well as including provisions for dismantling.

  4. The lithospheric shear-wave velocity structure of Saudi Arabia: Young volcanism in an old shield

    KAUST Repository

    Tang, Zheng

    2016-05-11

    We investigate the lithospheric shear-wave velocity structure of Saudi Arabia by conducting H-κ stacking analysis and jointly inverting teleseismic P-receiver functions and fundamental-mode Rayleigh wave group velocities at 56 broadband stations deployed by the Saudi Geological Survey (SGS). The study region, the Arabian plate, is traditionally divided into the western Arabian shield and the eastern Arabian platform: The Arabian shield itself is a complicated mélange of crustal material, composed of several Proterozoic terrains separated by ophiolite-bearing suture zones and dotted by outcropping Cenozoic volcanic rocks (locally known as harrats). The Arabian platform is primarily covered by 8 to 10 km of Paleozoic, Mesozoic and Cenozoic sedimentary rocks. Our results reveal high Vp/Vs ratios in the region of Harrat Lunayyir, which are interpreted as solidified magma intrusions from old magmatic episodes in the shield. Our results also indicate slow velocities and large upper mantle lid temperatures below the southern and northern tips of the Arabian shield, when compared with the values obtained for the central shield. We argue that our inferred patterns of lid velocity and temperature are due to heating by thermal conduction from the Afar plume (and, possibly, the Jordan plume), and that volcanism in western Arabia may result from small-scale adiabatic ascent of magma diapirs.

  5. Radiation Shielding Materials and Containers Incorporating Same

    Energy Technology Data Exchange (ETDEWEB)

    Mirsky, Steven M.; Krill, Stephen J.; and Murray, Alexander P.

    2005-11-01

    An improved radiation shielding material and storage systems for radioactive materials incorporating the same. The PYRolytic Uranium Compound (''PYRUC'') shielding material is preferably formed by heat and/or pressure treatment of a precursor material comprising microspheres of a uranium compound, such as uranium dioxide or uranium carbide, and a suitable binder. The PYRUC shielding material provides improved radiation shielding, thermal characteristic, cost and ease of use in comparison with other shielding materials. The shielding material can be used to form containment systems, container vessels, shielding structures, and containment storage areas, all of which can be used to house radioactive waste. The preferred shielding system is in the form of a container for storage, transportation, and disposal of radioactive waste. In addition, improved methods for preparing uranium dioxide and uranium carbide microspheres for use in the radiation shielding materials are also provided.

  6. Modular reactor head shielding system

    International Nuclear Information System (INIS)

    Jacobson, E. B.

    1985-01-01

    An improved modular reactor head shielding system is provided that includes a frame which is removably assembled on a reactor head such that no structural or mechanical alteration of the head is required. The shielding system also includes hanging assemblies to mount flexible shielding pads on trolleys which can be moved along the frame. The assemblies allow individual pivoting movement of the pads. The pivoting movement along with the movement allowed by the trolleys provides ease of access to any point on the reactor head. The assemblies also facilitate safe and efficient mounting of the pads directly to and from storage containers such that workers have additional shielding throughout virtually the entire installation and removal process. The flexible shielding pads are designed to interleave with one another when assembled around the reactor head for substantially improved containment of radiation leakage

  7. Estimation of temperature distribution in a reactor shield

    International Nuclear Information System (INIS)

    Agarwal, R.A.; Goverdhan, P.; Gupta, S.K.

    1989-01-01

    Shielding is provided in a nuclear reactor to absorb the radiations emanating from the core. The energy of these radiations appear in the form of heat. Concrete which is commonly used as a shielding material in nuclear power plants must be able to withstand the temperatures and temperature gradients appearing in the shield due to this heat. High temperatures lead to dehydration of the concrete and in turn reduce the shielding effectiveness of the material. Adequate cooling needs to be provided in these shields in order to limit the maximum temperature. This paper describes a method to estimate steady state and transient temperature distribution in reactor shields. The results due to loss of coolant in the coolant tubes have been studied and presented in the paper. (author). 5 figs

  8. Pressurizer /Auxiliary Spray Piping Stress Analysis For Determination Of Lead Shielding Maximum Allow Able Load

    International Nuclear Information System (INIS)

    Setjo, Renaningsih

    2000-01-01

    Piping stress analysis for PZR/Auxiliary Spray Lines Nuclear Power Plant AV Unit I(PWR Type) has been carried out. The purpose of this analysis is to establish a maximum allowable load that is permitted at the time of need by placing lead shielding on the piping system on class 1 pipe, Pressurizer/Auxiliary Spray Lines (PZR/Aux.) Reactor Coolant Loop 1 and 4 for NPP AV Unit one in the mode 5 and 6 during outage. This analysis is intended to reduce the maximum amount of radiation dose for the operator during ISI ( In service Inspection) period.The result shown that the maximum allowable loads for 4 inches lines for PZR/Auxiliary Spray Lines is 123 lbs/feet

  9. Radioprotection to the Gonads in Pediatric Pelvic Radiography: Effectiveness of Developed Bismuth Shield

    Directory of Open Access Journals (Sweden)

    Vahid Karami

    2017-06-01

    Full Text Available Background: The use and effectiveness of traditional lead gonad shields in pediatric pelvic radiography has been challenged by several literatures over the past two decades. The aim of this study was to develop a new radioprotective gonad shields to be use in pediatric pelvic radiography. Materials and Methods: The commercially available 0.06 mm lead equivalent bismuth garment has cropped squarely and used as ovarian shield to cover the entire region of pelvis. In order to prevent deterioration of image quality due to beam hardening artifacts, a 1-cm foam as spacer was located between the shield and patients pelvis. Moreover, we added a lead piece at the cranial position of the bismuth garment to absorb the scatter radiations to the radiosensitive organs. In girls, 49 radiographs with shield and 46 radiographs without shield was taken. The radiation dose was measured using thermoluminescent dosimeters (TLDs. Image quality assessments were performed using the European guidelines. For boys, the lead testicular shields was developed using 2 cm bismuth garment, added to the sides. The prevalence and efficacy of testicular shields was assessed in clinical practice fromFebruary 2016 to June 2016. Results: Without increasing the dose to the breast, thyroid and the lens of the eyes, the use of bismuth shield has reduced the entrance skin dose(ESD of the pelvis and radiation dose to the ovaries by 62.2% and 61.7%, respectively (P

  10. Development of HANARO ST3 shield

    International Nuclear Information System (INIS)

    Park, K. N.; Lee, J. S.; Shim, H. S.

    2004-12-01

    This report contains the design, fabrication and accurate installation of ST3 shield, which would be installed at ST3 beam port of HANARO. At first, we designed and fabricated ST3 shield casemate composed of 14 blocks. We filled it with heavy concrete, lead ingot and polyethylene that mixed B 4 C powder and epoxy. The average filling density of total shield casemate was 4.7g/cm 3 . The developed ST3 shield was installed at the ST3 beam port and the accuracy of installation for each beam path and channel was evaluated. We found that the extraction of neutron beam to meet the requirement of neutron spectrometer is possible. Also, we developed ancillary equipment such as BGU, quick shutter and exterior shield door for the effective opening and closing of neutron beam. As a result of this study, it was found that neutron spectrometer such as neutron reflectometer and high intensity powder diffractomater can be installed at the ST3 beam port

  11. Monte Carlo simulations for the space radiation superconducting shield project (SR2S).

    Science.gov (United States)

    Vuolo, M; Giraudo, M; Musenich, R; Calvelli, V; Ambroglini, F; Burger, W J; Battiston, R

    2016-02-01

    Astronauts on deep-space long-duration missions will be exposed for long time to galactic cosmic rays (GCR) and Solar Particle Events (SPE). The exposure to space radiation could lead to both acute and late effects in the crew members and well defined countermeasures do not exist nowadays. The simplest solution given by optimized passive shielding is not able to reduce the dose deposited by GCRs below the actual dose limits, therefore other solutions, such as active shielding employing superconducting magnetic fields, are under study. In the framework of the EU FP7 SR2S Project - Space Radiation Superconducting Shield--a toroidal magnetic system based on MgB2 superconductors has been analyzed through detailed Monte Carlo simulations using Geant4 interface GRAS. Spacecraft and magnets were modeled together with a simplified mechanical structure supporting the coils. Radiation transport through magnetic fields and materials was simulated for a deep-space mission scenario, considering for the first time the effect of secondary particles produced in the passage of space radiation through the active shielding and spacecraft structures. When modeling the structures supporting the active shielding systems and the habitat, the radiation protection efficiency of the magnetic field is severely decreasing compared to the one reported in previous studies, when only the magnetic field was modeled around the crew. This is due to the large production of secondary radiation taking place in the material surrounding the habitat. Copyright © 2016 The Committee on Space Research (COSPAR). Published by Elsevier Ltd. All rights reserved.

  12. Electron structure of atoms in laser plasma: The Debye shielding model

    International Nuclear Information System (INIS)

    Sako, Tokuei; Okutsu, Hiroshi; Yamanouchi, Kaoru

    2005-01-01

    The electronic structure and the energy spectra of multielectron atoms in laser plasmas are examined by the Debye shielding model. The effect of the plasma environment on the electrons bound in an atom is taken into account by introducing the screened Coulomb-type potentials into the electronic Hamiltonian of an atom in place of the standard nuclear attraction and electron repulsion potentials. The capabilities of this new Hamiltonian are demonstrated for He and Li in laser plasmas. (author)

  13. Electromagnetic analysis of the Faraday shield of the EAST ICRF antenna

    International Nuclear Information System (INIS)

    Yang Qingxi; Song Yuntao; Wu Songtao; Zhao Yanping

    2011-01-01

    Faraday shield is one of the important components of ICRF antenna for EAST. In view of the structural safety of the Faraday shield, the electromagnetic and structural analyses for the Faraday shield have been carried out by applying the finite element method and the formulas under the cases of plasma disruption and vertical displacement event (VDE). Results of the electromagnetic forces, the stresses distribution as well as the deformation in the Faraday shield have been obtained under the two cases. They meet the design requirements and provide the theoretical basis for the structural safety evaluation of the Faraday shield. (authors)

  14. Acoustic Metacages for Omnidirectional Sound Shielding

    OpenAIRE

    Shen, Chen; Xie, Yangbo; Li, Junfei; Cummer, Steven A.; Jing, Yun

    2017-01-01

    Conventional sound shielding structures typically prevent fluid transport between the exterior and interior. A design of a two-dimensional acoustic metacage with subwavelength thickness which can shield acoustic waves from all directions while allowing steady fluid flow is presented in this paper. The structure is designed based on acoustic gradient-index metasurfaces composed of open channels and shunted Helmholtz resonators. The strong parallel momentum on the metacage surface rejects in-pl...

  15. Shielding design of ITER pressure suppression system

    International Nuclear Information System (INIS)

    Yamauchi, Michinori; Sato, Satoshi; Nishitani, Takeo; Kawasaki, Hiromitsu

    2006-01-01

    The duct shield from streaming D-T neutrons has been designed for the ITER pressure suppression system. Streaming calculations are performed with the DUCT-III code for the region from the inlet of the pressure relief line to the rupture disk. Next, the neutron permeation through the shield is studied by Monte Carlo calculations with the MCNP code. It is found that 0.15 m thick iron shield is enough to suppress the permeating component from the outside. In addition, it is suggested that the volume of the shield can be reduced by about 30% if the optimized iron shield structure having localized thickness across intense permeation paths is employed to shield the pressure suppression line. (T.I.)

  16. Lithospheric structure of the Arabian Shield and Platform from complete regional waveform modelling and surface wave group velocities

    Science.gov (United States)

    Rodgers, Arthur J.; Walter, William R.; Mellors, Robert J.; Al-Amri, Abdullah M. S.; Zhang, Yu-Shen

    1999-09-01

    Regional seismic waveforms reveal significant differences in the structure of the Arabian Shield and the Arabian Platform. We estimate lithospheric velocity structure by modelling regional waveforms recorded by the 1995-1997 Saudi Arabian Temporary Broadband Deployment using a grid search scheme. We employ a new method whereby we narrow the waveform modelling grid search by first fitting the fundamental mode Love and Rayleigh wave group velocities. The group velocities constrain the average crustal thickness and velocities as well as the crustal velocity gradients. Because the group velocity fitting is computationally much faster than the synthetic seismogram calculation this method allows us to determine good average starting models quickly. Waveform fits of the Pn and Sn body wave arrivals constrain the mantle velocities. The resulting lithospheric structures indicate that the Arabian Platform has an average crustal thickness of 40 km, with relatively low crustal velocities (average crustal P- and S-wave velocities of 6.07 and 3.50 km s^-1 , respectively) without a strong velocity gradient. The Moho is shallower (36 km) and crustal velocities are 6 per cent higher (with a velocity increase with depth) for the Arabian Shield. Fast crustal velocities of the Arabian Shield result from a predominantly mafic composition in the lower crust. Lower velocities in the Arabian Platform crust indicate a bulk felsic composition, consistent with orogenesis of this former active margin. P- and S-wave velocities immediately below the Moho are slower in the Arabian Shield than in the Arabian Platform (7.9 and 4.30 km s^-1 , and 8.10 and 4.55 km s^-1 , respectively). This indicates that the Poisson's ratios for the uppermost mantle of the Arabian Shield and Platform are 0.29 and 0.27, respectively. The lower mantle velocities and higher Poisson's ratio beneath the Arabian Shield probably arise from a partially molten mantle associated with Red Sea spreading and continental

  17. Radiation shield for PWR reactors

    International Nuclear Information System (INIS)

    Esenov, Amra; Pustovgar, Andrey

    2013-01-01

    One of the chief structures of a reactor pit is a 'dry' shield. Setting up a 'dry' shield includes the technologically complex process of thermal processing of serpentinite concrete. Modern advances in the area of materials technology permit avoiding this complex and demanding procedure, and this significantly decreases the duration, labor intensity, and cost of setting it up. (orig.)

  18. Structural Shielding Design and Evaluation for Megavoltage X- and Gamma-Ray Radiotherapy Facilities.

    Science.gov (United States)

    Glasgow, Glenn P

    2006-09-01

    Structural Shielding Design and Evaluation for Megavoltage X- and Gamma-Ray Radiotherapy Facilities NCRP Report No. 151, 2005, 246 pp. (Hardcover $100). National Council on Radiation Protection and Measurements, 7910 Woodmont Avenue, Suite 400, Bethesda, MD 20814-3095. ISBN-10 0-0929600-87-8; http://www.NCRPonline.org. © 2006 American Association of Physicists in Medicine.

  19. Mantle transition zone structure beneath the Canadian Shield

    Science.gov (United States)

    Thompson, D. A.; Helffrich, G. R.; Bastow, I. D.; Kendall, J. M.; Wookey, J.; Eaton, D. W.; Snyder, D. B.

    2010-12-01

    The Canadian Shield is underlain by one of the deepest and most laterally extensive continental roots on the planet. Seismological constraints on the mantle structure beneath the region are presently lacking due to the paucity of stations in this remote area. Presented here is a receiver function study on transition zone structure using data from recently deployed seismic networks from the Hudson Bay region. High resolution images based on high signal-to-noise ratio data show clear arrivals from the 410 km and 660 km discontinuities, revealing remarkably little variation in transition zone structure. Transition zone thickness is close to the global average (averaging 245 km across the study area), and any deviations in Pds arrival time from reference Earth models can be readily explained by upper-mantle velocity structure. The 520 km discontinuity is not a ubiquitous feature, and is only weakly observed in localised areas. These results imply that the Laurentian root is likely confined to the upper-mantle and if any mantle downwelling exists, possibly explaining the existence of Hudson Bay, it is also confined to the upper 400 km. Any thermal perturbations at transition zone depths associated with the existence of the root, whether they be cold downwellings or elevated temperatures due to the insulating effect of the root, are thus either non-existent or below the resolution of the study.

  20. A study on the shielding element using Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki Jeong [Dept. of Radiology, Konkuk University Medical Center, Seoul (Korea, Republic of); Shim, Jae Goo [Dept. of Radiologic Technology, Daegu Health College, Daegu (Korea, Republic of)

    2017-06-15

    In this research, we simulated the elementary star shielding ability using Monte Carlo simulation to apply medical radiation shielding sheet which can replace existing lead. In the selection of elements, mainly elements and metal elements having a large atomic number, which are known to have high shielding performance, recently, various composite materials have improved shielding performance, so that weight reduction, processability, In consideration of activity etc., 21 elements were selected. The simulation tools were utilized Monte Carlo method. As a result of simulating the shielding performance by each element, it was estimated that the shielding ratio is the highest at 98.82% and 98.44% for tungsten and gold.

  1. Integrated evaluation of the geology, aero gamma spectrometry and aero magnetometry of the Sul-Riograndense Shield, southernmost Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, Leo A.; Savian, Jairo F., E-mail: leo.hartmann@ufrgs.br [Universidade Federal do Rio Grande do Sul (UFRS), Porto Alegre, RS (Brazil). Instituto de Geociencias; Lopes, William R. [Servico Geologico do Brasil (CPRM), Porto Alegre, RS (Brazil). Gerencia de Geologia e Mineracao

    2016-03-15

    An integrated evaluation of geology, aero gamma spectrometry and aero magnetometry of the Sul-Riograndense Shield is permitted by the advanced stage of understanding of the geology and geochronology of the southern Brazilian Shield and a 2010 airborne geophysical survey. Gamma rays are registered from the rocks near the surface and thus describe the distribution of major units in the shield, such as the Pelotas batholith, the juvenile São Gabriel terrane, the granulite-amphibolite facies Taquarembo terrane and the numerous granite intrusions in the foreland. Major structures are also observed, e.g., the Dorsal de Cangucu shear. Magnetic signals register near surface crustal compositions (analytic signal) and total crust composition (total magnetic signal), so their variation as measured indicates either shallow or whole crustal structures. The Cacapava shear is outstanding on the images as is the magnetic low along the N-S central portion of the shield. These integrated observations lead to the deepening of the understanding of the largest and even detailed structures of the Sul-Riograndense Shield, some to be correlated to field geology in future studies. Most significant is the presence of different provinces and their limits depending on the method used for data acquisition - geology, aero gamma spectrometry or aero magnetometry. (author)

  2. Andoma segment of southeastern margin of fennoscandian shield: Structure and evolution

    Science.gov (United States)

    Kolodyazhny, S. Yu.; Baluev, A. S.; Terekhov, E. N.

    2016-07-01

    The components of deformation related to endogenic (tectonic) and exogenic (glaciotectonic, gravitational sliding) factors are considered in the sedimentary platform cover by a study of Andoma dislocations in the Upper Devonian sedimentary rocks of the Lake Onega district. These structures are localized in the eponymous segment of the southeastern margin of the Fennoscandian (Baltic) Shield; indications of high tectonic activity are noted along this margin. As has been shown by a structural study, the development of the Andoma structure is caused by long-term (Late Devonian-Quaternary) multistage deformations related to tectonic factors and, to a lesser degree, glaciotectonics. The consecutive stages of synsedimentation normal faulting and landsliding, bedding-plane gliding, various forms of shear flow in a regime of transpression, glaciotectonic thrusting, and neotectonic transpression are recognized in the deformation history.

  3. Equipment for shielding the gonad region while performing radiographs

    International Nuclear Information System (INIS)

    Starp, F.

    1979-01-01

    The shield consists of a fixed square central lead plate and, associated to it, lead sheets arranged linear displaceable and/or rotatable, by means of which the superficial extent may be variated. For protection from damaging and contamination this shield itself is enclosed by a casing in the form of two cup-shaped discs e.g. from plexiglas put one above the other at the edge. (DG) 891 HP/DG 892 MKO [de

  4. Radiation shielding

    International Nuclear Information System (INIS)

    Yue, D.D.

    1979-01-01

    Details are given of a cylindrical electric penetration assembly for carrying instrumentation leads, used in monitoring the performance of a nuclear reactor, through the containment wall of the reactor. Effective yet economical shielding protection against both fast neutron and high-energy gamma radiation is provided. Adequate spacing within the assembly allows excessive heat to be efficiently dissipated and means of monitoring all potential radiation and gas leakage paths are provided. (UK)

  5. Innovative technologies for Faraday shield cooling

    International Nuclear Information System (INIS)

    Rosenfeld, J.H.; Lindemuth, J.E.; North, M.T.; Goulding, R.H.

    1995-01-01

    Alternative advanced technologies are being evaluated for use in cooling the Faraday shields used for protection of ion cyclotron range of frequencies (ICR) antennae in Tokamaks. Two approaches currently under evaluation include heat pipe cooling and gas cooling. A Monel/water heat pipe cooled Faraday shield has been successfully demonstrated. Heat pipe cooling offers the advantage of reducing the amount of water discharged into the Tokamak in the event of a tube weld failure. The device was recently tested on an antenna at Oak Ridge National Laboratory. The heat pipe design uses inclined water heat pipes with warm water condensers located outside of the plasma chamber. This approach can passively remove absorbed heat fluxes in excess of 200 W/cm 2 ;. Helium-cooled Faraday shields are also being evaluated. This approach offers the advantage of no liquid discharge into the Tokamak in the event of a tube failure. Innovative internal cooling structures based on porous metal cooling are being used to develop a helium-cooled Faraday shield structure. This approach can dissipate the high heat fluxes typical of Faraday shield applications while minimizing the required helium blower power. Preliminary analysis shows that nominal helium flow and pressure drop can sufficiently cool a Faraday shield in typical applications. Plans are in progress to fabricate and test prototype hardware based on this approach

  6. Double-layer neutron shield design as neutron shielding application

    Science.gov (United States)

    Sariyer, Demet; Küçer, Rahmi

    2018-02-01

    The shield design in particle accelerators and other high energy facilities are mainly connected to the high-energy neutrons. The deep penetration of neutrons through massive shield has become a very serious problem. For shielding to be efficient, most of these neutrons should be confined to the shielding volume. If the interior space will become limited, the sufficient thickness of multilayer shield must be used. Concrete and iron are widely used as a multilayer shield material. Two layers shield material was selected to guarantee radiation safety outside of the shield against neutrons generated in the interaction of the different proton energies. One of them was one meter of concrete, the other was iron-contained material (FeB, Fe2B and stainless-steel) to be determined shield thicknesses. FLUKA Monte Carlo code was used for shield design geometry and required neutron dose distributions. The resulting two layered shields are shown better performance than single used concrete, thus the shield design could leave more space in the interior shielded areas.

  7. Measurements and Monte-Carlo simulations of the particle self-shielding effect of B4C grains in neutron shielding concrete

    Science.gov (United States)

    DiJulio, D. D.; Cooper-Jensen, C. P.; Llamas-Jansa, I.; Kazi, S.; Bentley, P. M.

    2018-06-01

    A combined measurement and Monte-Carlo simulation study was carried out in order to characterize the particle self-shielding effect of B4C grains in neutron shielding concrete. Several batches of a specialized neutron shielding concrete, with varying B4C grain sizes, were exposed to a 2 Å neutron beam at the R2D2 test beamline at the Institute for Energy Technology located in Kjeller, Norway. The direct and scattered neutrons were detected with a neutron detector placed behind the concrete blocks and the results were compared to Geant4 simulations. The particle self-shielding effect was included in the Geant4 simulations by calculating effective neutron cross-sections during the Monte-Carlo simulation process. It is shown that this method well reproduces the measured results. Our results show that shielding calculations for low-energy neutrons using such materials would lead to an underestimate of the shielding required for a certain design scenario if the particle self-shielding effect is not included in the calculations.

  8. Shielding calculation for bremsstrahlung from β-emitters

    International Nuclear Information System (INIS)

    Ichimiya, Tsutomu

    1990-01-01

    Accompanying the revision of radiation injury prevention law, the shielding calculation method for photon corresponding to the dose equivalent was shown. However, regarding the electron from β decay nuclide and bremsstrahlung caused by shielding material, the shielding calculation method corresponding to the 1 cm dose equivalent has not been reported, hence, in this report, the spectrum of β-ray is calculated and the 1 cm dose equivalent transmission rate of the bremsstrahlung was calculated for three kinds of shielding materials (iron, lead, concrete). As the result of consideration, it is sufficient to think about the bremsstrahlung due to negative electron emission accompanying β-decay. In β-decay, electrons which constitute the continuous spectrum with maximum energy are emitted. The shape of the spectrum differs with nuclides. The maximum energy of β-ray of generally used nuclides is mostly below 3MeV and, besides, the electron ray itself is easily shielded, while the strength of bremsstrahlung depends on the atomic number of shielding materials and its generating mechanism is complicated. In this report, the actual shielding calculation method for bremsstrahlung is shown with regard to the most frequently used β-decay nuclides. (M.T.)

  9. Discussions for the shielding materials of synchrotron radiation beamline hutches

    International Nuclear Information System (INIS)

    Asano, Y.

    2006-01-01

    Many synchrotron radiation facilities are now under operation such as E.S.R.F., APS, and S.P.ring-8. New facilities with intermediated stored electron energy are also under construction and designing such as D.I.A.M.O.N.D., S.O.L.E.I.L., and S.S.R.F.. At these third generation synchrotron radiation facilities, the beamline shielding as well as the bulk shield is very important for designing radiation safety because of intense and high energy synchrotron radiation beam. Some reasons employ lead shield wall for the synchrotron radiation beamlines. One is narrow space for the construction of many beamlines at the experimental hall, and the other is the necessary of many movable mechanisms at the beamlines, for examples. Some cases are required to shield high energy neutrons due to stored electron beam loss and photoneutrons due to gas Bremsstrahlung. Ordinary concrete and heavy concrete are coming up to shield material of synchrotron radiation beamline hutches. However, few discussions have been performed so far for the shielding materials of the hutches. In this presentation, therefore, we will discuss the characteristics of the shielding conditions including build up effect for the beamline hutches by using the ordinary concrete, heavy concrete, and lead for shielding materials with 3 GeV and 8 GeV class synchrotron radiation source. (author)

  10. Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material

    International Nuclear Information System (INIS)

    Gordon, G.

    2004-01-01

    Stress corrosion cracking is one of the most common corrosion-related causes for premature breach of metal structural components. Stress corrosion cracking is the initiation and propagation of cracks in structural components due to three factors that must be present simultaneously: metallurgical susceptibility, critical environment, and static (or sustained) tensile stresses. This report was prepared according to ''Technical Work Plan for: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]). The purpose of this report is to provide an evaluation of the potential for stress corrosion cracking of the engineered barrier system components (i.e., the drip shield, waste package outer barrier, and waste package stainless steel inner structural cylinder) under exposure conditions consistent with the repository during the regulatory period of 10,000 years after permanent closure. For the drip shield and waste package outer barrier, the critical environment is conservatively taken as any aqueous environment contacting the metal surfaces. Appendix B of this report describes the development of the SCC-relevant seismic crack density model (SCDM). The consequence of a stress corrosion cracking breach of the drip shield, the waste package outer barrier, or the stainless steel inner structural cylinder material is the initiation and propagation of tight, sometimes branching, cracks that might be induced by the combination of an aggressive environment and various tensile stresses that can develop in the drip shields or the waste packages. The Stainless Steel Type 316 inner structural cylinder of the waste package is excluded from the stress corrosion cracking evaluation because the Total System Performance Assessment for License Application (TSPA-LA) does not take credit for the inner cylinder. This document provides a detailed description of the process-level models that can be applied to assess the performance of Alloy 22

  11. Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material

    Energy Technology Data Exchange (ETDEWEB)

    G. Gordon

    2004-10-13

    Stress corrosion cracking is one of the most common corrosion-related causes for premature breach of metal structural components. Stress corrosion cracking is the initiation and propagation of cracks in structural components due to three factors that must be present simultaneously: metallurgical susceptibility, critical environment, and static (or sustained) tensile stresses. This report was prepared according to ''Technical Work Plan for: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]). The purpose of this report is to provide an evaluation of the potential for stress corrosion cracking of the engineered barrier system components (i.e., the drip shield, waste package outer barrier, and waste package stainless steel inner structural cylinder) under exposure conditions consistent with the repository during the regulatory period of 10,000 years after permanent closure. For the drip shield and waste package outer barrier, the critical environment is conservatively taken as any aqueous environment contacting the metal surfaces. Appendix B of this report describes the development of the SCC-relevant seismic crack density model (SCDM). The consequence of a stress corrosion cracking breach of the drip shield, the waste package outer barrier, or the stainless steel inner structural cylinder material is the initiation and propagation of tight, sometimes branching, cracks that might be induced by the combination of an aggressive environment and various tensile stresses that can develop in the drip shields or the waste packages. The Stainless Steel Type 316 inner structural cylinder of the waste package is excluded from the stress corrosion cracking evaluation because the Total System Performance Assessment for License Application (TSPA-LA) does not take credit for the inner cylinder. This document provides a detailed description of the process-level models that can be applied to assess the

  12. AP1000 shield building: a constructability challenge

    International Nuclear Information System (INIS)

    Di Giuseppe, Giovanni; Bonanno, Domenico

    2010-01-01

    The AP1000 Shield Building, an enhanced structure which surrounds the containment vessel, consists of standard Reinforced Concrete (RC) and composite Steel and Concrete (SC) construction. In the SC module the surface steel plates, (with attached shear studs and angles) filled with concrete, act as the steel reinforcement in concrete. This is a relatively new design technology that required the appropriate use of structural codes, supplemented with information from applicable tests on similar composite steel and concrete construction. Being a newer design concept, existing codes do not provide explicit guidance on SC construction so a review of literature and test data on composite structures similar to AP1000 shield building was done in order to confirm the technical basis for the design. The SC walls, air inlet structure and roof of the Shield Building will be constructed using modular construction practices and then transported to site and lifted into place. These modules, working also as permanent form-work, will be filled with high strength Self- Consolidating Concrete. (SCC) This paper provides a focused and integrated presentation of the enhanced shield building design methodology, testing, constructability and inspection. (authors)

  13. Improved Metal-Polymeric Laminate Radiation Shielding, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In this proposed Phase I program, a multifunctional lightweight radiation shield composite will be developed and fabricated. This structural radiation shielding will...

  14. Comparison of some lead and non-lead based glass systems, standard shielding concretes and commercial window glasses in terms of shielding parameters in the energy region of 1 keV-100 GeV: A comparative study

    International Nuclear Information System (INIS)

    Kurudirek, Murat; Ozdemir, Yueksel; Simsek, Onder; Durak, Ridvan

    2010-01-01

    The effective atomic numbers, Z eff of some glass systems with and without Pb have been calculated in the energy region of 1 keV-100 GeV including the K absorption edges of high Z elements present in the glass. Also, these glass systems have been compared with some standard shielding concretes and commercial window glasses in terms of mean free paths and total mass attenuation coefficients in the continuous energy range. Comparisons with experiments were also provided wherever possible for glasses. It has been observed that the glass systems without Pb have higher values of Z eff than that of Pb based glasses at some high energy regions even if they have lower mean atomic numbers than Pb based glasses. When compared with some standard shielding concretes and commercial window glasses, generally it has been shown that the given glass systems have superior properties than concretes and window glasses with respect to the radiation-shielding properties, thus confirming the availability of using these glasses as substitutes for some shielding concretes and commercial window glasses to improve radiation-shielding properties in the continuous energy region.

  15. Protein structure refinement using a quantum mechanics-based chemical shielding predictor.

    Science.gov (United States)

    Bratholm, Lars A; Jensen, Jan H

    2017-03-01

    The accurate prediction of protein chemical shifts using a quantum mechanics (QM)-based method has been the subject of intense research for more than 20 years but so far empirical methods for chemical shift prediction have proven more accurate. In this paper we show that a QM-based predictor of a protein backbone and CB chemical shifts (ProCS15, PeerJ , 2016, 3, e1344) is of comparable accuracy to empirical chemical shift predictors after chemical shift-based structural refinement that removes small structural errors. We present a method by which quantum chemistry based predictions of isotropic chemical shielding values (ProCS15) can be used to refine protein structures using Markov Chain Monte Carlo (MCMC) simulations, relating the chemical shielding values to the experimental chemical shifts probabilistically. Two kinds of MCMC structural refinement simulations were performed using force field geometry optimized X-ray structures as starting points: simulated annealing of the starting structure and constant temperature MCMC simulation followed by simulated annealing of a representative ensemble structure. Annealing of the CHARMM structure changes the CA-RMSD by an average of 0.4 Å but lowers the chemical shift RMSD by 1.0 and 0.7 ppm for CA and N. Conformational averaging has a relatively small effect (0.1-0.2 ppm) on the overall agreement with carbon chemical shifts but lowers the error for nitrogen chemical shifts by 0.4 ppm. If an amino acid specific offset is included the ProCS15 predicted chemical shifts have RMSD values relative to experiments that are comparable to popular empirical chemical shift predictors. The annealed representative ensemble structures differ in CA-RMSD relative to the initial structures by an average of 2.0 Å, with >2.0 Å difference for six proteins. In four of the cases, the largest structural differences arise in structurally flexible regions of the protein as determined by NMR, and in the remaining two cases, the large structural

  16. Calculation of the structural shielding of the radiotherapy treatment room equipped with a linear accelerator type Tomo therapy Hi-Art in the Oncology Center of Chihuahua, Mexico

    International Nuclear Information System (INIS)

    Caballero G, C. A.; Plascencia, J. C.; Vargas V, M. X.; Toledo J, P.

    2010-09-01

    The helicoid tomo therapy is an external radiotherapy system of modulated intensity, guided by image, in which the radiation is imparted to the patient using a narrow radiation beam in helicoid form, in a similar way to the scanning process with a computerized tomography. The tomo therapy equipment (Tomo Therapy Hi-Art) consists in an electrons linear accelerator with acceleration voltages of 6 MV for treatment and 3.5 MV for image, coupled to a ring that turn around the patient as this is transferred through this ring in perpendicular sense to the radiation beam. The radiation beam is narrow because has the maximum size of 5 x 40 cm 2 in the isocenter. The intensity modulation of the beam is carried out with a binary dynamic collimator of 64 crisscross sheets, and the guide by image though a system of megavoltage computerized tomography. Opposed to the radiation beam, also coupled to the rotational ring, a group of lead plates exists with a total thickness of 13 cm that acts as barrier of the primary radiation beam. The special configuration of the tomography equipment makes to have the following characteristics: 1) the presence of the lead barrier of the equipment reduces the intensity of the primary beam that reaches the bunker walls in considerable way, 2) the disperse and leakage radiations are increased with regard to a conventional accelerator due to the increase in the necessary irradiation time to produce modulated intensity fields by means of the narrow radiation beam. These special characteristics of the tomo therapy equipment make that particularities exist in the application of the formulations for structural shielding calculations that appears in the NCRP reports 49, NCRP 151 and IAEA-SRS-47. For this reason, several researches have development analytic models based on geometric considerations of continuous rotation of the equipment ring to determine the shielding requirements for the primary beam, the dispersed and leakage radiation in tomo therapy

  17. The assembly of the disk shielding is finished.

    CERN Multimedia

    Vincent Hedberg

    At the end of March, the shielding project engineer, Jan Palla, could draw a sigh of relief when the fourth and final rotation of the disk shielding was carried out without incident. The two 80-ton heavy shielding assemblies were built in a horizontal position and they had to be first turned upside-down and then rotated to a vertical position during the assembly. The relatively thin disk plate with a diameter of 9 meters, made this operation quite delicate and a lot of calculation work and strengthening of the shielding was carried out before the rotations could take place. The disk shielding is being turned upside-down. The stainless steel cylinder in the centre supports the shielding as well as the small muon wheel. The two disk shielding assemblies consist of different materials such as bronze, gray steel, cast iron, stainless steel, boron doped polyethylene and lead. The project is multinational with the major pieces having been made by companies in Armenia, Serbia, Spain, Bulgaria, Italy, Slovaki...

  18. Airborne concentrations of toxic metals resulting from the use of low melting point lead alloys to construct radiotherapy shielding

    International Nuclear Information System (INIS)

    McCullough, E.C.; Senjem, D.H.

    1981-01-01

    Determinations of airborne concentrations of lead, cadmium, bismuth, and tin were made above vessels containing a fusible lead alloy (158 0 F melting point) commonly used for construction of radiotherapy blocks. Fume concentrations were determined by collection on a membrane filter and analysis by atomic absorption spectrophotometry. Samples were obtained for alloy temperatures of 200 0 , 400 0 , and 600 0 F. In all instances, concentrations were much lower than the applicable occupational limits for continuous exposure. The results of this study indicate that the use of a vented hood as a means of reducing air concentrations of toxic metals above and near vessels containing low temperature melting point lead allows commonly used in construction of radiotherapy shields appears unjustifiable. However, proper handling procedures should be observed to avoid entry into the body via alternate pathways (e.g., ingestion or skin absorption). Transmission data of a non-cadmium containing lead alloy with a melting point of 203 0 F was ascertained and is reported on

  19. Neutral and plasma shielding model for pellet ablation

    International Nuclear Information System (INIS)

    Houlberg, W.A.; Milora, S.L.; Attenberger, S.E.

    1987-10-01

    The neutral gas shielding model for ablation of frozen hydrogenic pellets is extended to include the effects of an initial Maxwelliam distribution of incident electron energies; a cold plasma shield outside the neutral shield and extended along the magnetic field; energetic neutral beam ions and alpha particles; and self-limiting electron ablation in the collisionless plasma limit. Including the full electron distribution increases ablation, but adding the cold ionized shield reduces ablation; the net effect is a modest reduction in pellet penetration compared with the monoenergetic electron neutral shielding model with no plasma shield. Unlike electrons, fast ions can enter the neutral shield directly without passing through the cold ionized shield because their gyro-orbits are typically larger than the diameter of the cold plasma tube. Fast alpha particles should not enhance the ablation rate unless their population exceeds that expected from local classical thermalization. Fast beam ions, however, may enhance ablation in the plasma periphery if their population is high enough. Self-limiting ablation in the collisionless limit leads to a temporary distortion of the original plasma electron Maxwellian distribution function through preferential depopulation of the higher-energy electrons. 23 refs., 9 figs

  20. Light shielding apparatus

    Science.gov (United States)

    Miller, Richard Dean; Thom, Robert Anthony

    2017-10-10

    A light shielding apparatus for blocking light from reaching an electronic device, the light shielding apparatus including left and right support assemblies, a cross member, and an opaque shroud. The support assemblies each include primary support structure, a mounting element for removably connecting the apparatus to the electronic device, and a support member depending from the primary support structure for retaining the apparatus in an upright orientation. The cross member couples the left and right support assemblies together and spaces them apart according to the size and shape of the electronic device. The shroud may be removably and adjustably connectable to the left and right support assemblies and configured to take a cylindrical dome shape so as to form a central space covered from above. The opaque shroud prevents light from entering the central space and contacting sensitive elements of the electronic device.

  1. Determination of boron in Jabroc wood used as a shielding material in nuclear reactors

    International Nuclear Information System (INIS)

    Kamble, Granthali S.; Manisha, V.; Venkatesh, K.

    2015-01-01

    Jabroc are non-impregnated, densified wood laminates developed commercially for a wide range of industrial applications. Jabroc can be used with other neutron shielding materials such as Lead to form complex shielding structures. Its relative light weight and cleanliness in handling are additional features that make it a suitable candidate for the standard design of neutron shielding equipment. Jabroc can also be impregnated with Boron up to a maximum of 4% to be used in areas where Gamma radiation produced on Neutron capture reaches unacceptable dose rates. Boron impregnated Jabroc wood finds application in TAPS 3 and 4 as a shielding material for the Ion Chambers and the Horizontal Flux Units (HFU). The shielding property of this material is optimized by incorporating requisite amount of boron in wood. Boron content in this material has to be determined accurately prior to its use in the nuclear reactors. In this work a method was standardized to determine boron in Jabroc wood samples to check for conformance to specifications. The wood sample flakes were wetted with saturated barium hydroxide solution and dries under IR. The sample was ashed in a muffle furnace at 600℃ for 2 h

  2. Assessment of engine noise shielding by the wings of current turbofan aircraft

    NARCIS (Netherlands)

    Alves Vieira, A.E.; Snellen, M.; Simons, D.G.; Gibbs, B.

    2017-01-01

    The shielding of engine noise by the aircraft wings and fuselage can lead to a significant reduction on perceived noise on ground. Most research on noise shielding is focused on BlendedWing Body (BWB) configurations because of the large dimension of the fuselage. However, noise shielding is also

  3. Secondary gamma-ray data for shielding calculation

    International Nuclear Information System (INIS)

    Miyasaka, Sunichi

    1979-01-01

    In deep penetration transport calculations, the integral design parameters is determined mainly by secondary particles which are produced by interactions of the primary radiation with materials. The shield thickness and the biological dose rate at a given point of a bulk shield are determined from the contribution from secondary gamma rays. The heat generation and the radiation damage in the structural and shield materials depend strongly on the secondary gamma rays. In this paper, the status of the secondary gamma ray data and its further problems are described from the viewpoint of shield design. The secondary gamma-ray data in ENDF/B-IV and POPOP4 are also discussed based on the test calculations made for several shield assemblies. (author)

  4. Design lead shielded casks for shipment and spent fuel from power reactors to reprocessing plant at Tarapur

    International Nuclear Information System (INIS)

    Seetharamaiah, P.

    1975-01-01

    Spent fuels from the Tarapur and Rajasthan Atomic Power Stations (TAPS and RAPS) are shipped to Fuel Reprocessing Plant at Tarapur in heavily lead shielded casks weighing about 65 tonnes as they are highly radioactive. The design of the casks has to meet stringemt requirements of safety and the integrity should be ensured to contain activity under credible accidents during handling and transportation. The paper presents the design of two casks for TAPS and RAPS spent fuel transportation particularly with reference to stress analysis considerations. The analysis also includes the handling gadgets and tie down attachments on the rail wagon and road trailer. (author)

  5. Radiation shielding device

    International Nuclear Information System (INIS)

    Nakagawa, Takahiro; Yamagami, Makoto.

    1996-01-01

    A fixed shielding member made of a radiation shielding material is constituted in perpendicular to an opening formed on radiation shielding walls. The fixed shielding member has one side opened and has other side, the upper portion and the lower portion disposed in close contact with the radiation shielding walls. Movable shielding members made of a radiation shielding material are each disposed openably on both side of the fixed shielding member. The movable shielding member has a shaft as a fulcrum on one side thereof for connecting it to the radiation shielding walls. The other side has a handle attached for opening/closing the movable shielding member. Upon access of an operator, when each one of the movable shielding members is opened/closed on every time, leakage of linear or scattered radiation can be prevented. Even when both of the movable shielding members are opened simultaneously, the fixed shielding member and the movable shielding members form labyrinth to prevent leakage of linear radioactivity. (I.N.)

  6. Radioprotection to the Gonads in Pediatric Pelvic Radiography: Effectiveness of Developed Bismuth Shield

    OpenAIRE

    Vahid Karami; Mansour Zabihzadeh; Nasim Shams; Mehrdad Golami

    2017-01-01

    Background: The use and effectiveness of traditional lead gonad shields in pediatric pelvic radiography has been challenged by several literatures over the past two decades. The aim of this study was to develop a new radioprotective gonad shields to be use in pediatric pelvic radiography. Materials and Methods: The commercially available 0.06 mm lead equivalent bismuth garment has cropped squarely and used as ovarian shield to cover the entire region of pelvis. In order to prevent deteriorati...

  7. Fabrication, characterization and gamma rays shielding properties of nano and micro lead oxide-dispersed-high density polyethylene composites

    Science.gov (United States)

    Mahmoud, Mohamed E.; El-Khatib, Ahmed M.; Badawi, Mohamed S.; Rashad, Amal R.; El-Sharkawy, Rehab M.; Thabet, Abouzeid A.

    2018-04-01

    Polymer composites of high-density polyethylene (HD-PE) filled with powdered lead oxide nanoparticles (PbO NPs) and bulk lead oxide (PbO Blk) were prepared with filler weight fraction [10% and 50%]. These polymer composites were investigated for radiation-shielding of gamma-rays emitted from radioactive point sources [241Am, 133Ba, 137Cs, and 60Co]. The polymer was found to decrease the heaviness of the shielding material and increase the flexibility while the metal oxide fillers acted as principle radiation attenuators in the polymer composite. The prepared composites were characterized by Fourier transform infrared spectrophotometer (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscope (SEM), Brunauer-Emmett-Teller surface area (BET) and field emission transmission electron microscope (FE-TEM). The morphological analysis of the assembled composites showed that, PbO NPs and PbO Blk materials exhibited homogenous dispersion in the polymer-matrix. Thermogravimetric analysis (TGA) demonstrated that the thermal-stability of HD-PE was enhanced in the presence of both PbO Blk and PbO NPs. The results declared that, the density of polymer composites was increase with the percentage of filler contents. The highest density value was identified as 1.652 g cm-3 for 50 wt% of PbO NPs. Linear attenuation coefficients (μ) have been estimated from the use of XCOM code and measured results. Reasonable agreement was attended between theoretical and experimental results. These composites were also found to display excellent percentage of heaviness with respect to other conventional materials.

  8. Investigation of the effect of barium content on the structural and gamma-ray shielding properties of bismuth borate glasses

    International Nuclear Information System (INIS)

    Parminder Kaur; Singh, K.J.; Kulwinder Kaur; Anand, Vikas; Dogra, Mridula

    2017-01-01

    Glasses doped with heavy metal oxides have been proposed to shield the hazardous gamma rays originating from nuclear reactors as alternative to the conventional concretes. In this work, transparent glasses with composition 65Bi_2O_3-xBaO-(35-x) B_2O_3 (with x =0, 4, 8 wt %) have been prepared by using melt quenching technique in the laboratory. XRD and FTIR studies have been undertaken to explore the structural properties. The amorphous nature of the prepared samples is confirmed by XRD studies. Structural changes in the system have been explored by FTIR studies. The FTIR results reveal the conversion of (BO_3) triangular units to (BO_4) tetrahedral units with the addition of barium oxide along with the creation of non-bridging oxygen in the prepared glass system. Gamma-ray shielding properties have been explored with the help of WinXCom software developed by National Institute Standards and Technology at photon energy 662 keV. Gamma ray shielding properties in terms of mass attenuation coefficient, half value layer, tenth value layer and mean free path have been found to be superior as compared to the ordinary as well as barite concrete. Therefore, it is speculated that our prepared glass samples can serve as better gamma ray shielding materials. (author)

  9. Dosimetry and shielding

    International Nuclear Information System (INIS)

    Farinelli, U.

    1977-01-01

    Today, reactor dosimetry and shielding have wide areas of overlap as concerns both problems and methods. Increased interchange of results and know-how would benefit both. The areas of common interest include calculational methods, sensitivity studies, theoretical and experimental benchmarks, cross sections and other nuclear data, multigroup libraries and procedures for their adjustment, experimental techniques and damage functions. This paper reviews the state-of-the-art and the latest development in each of these areas as far as shielding is concerned, and suggests a number of interactions that could be profitable for reactor dosimetry. Among them, re-evaluation of the potentialities of calculational methods (in view of the recent developments) in predicting radiation environments of interest; the application of sensitivity analysis to dosimetry problems; a common effort in the field of theoretical benchmarks; the use of the shielding one-material propagation experiments as reference spectra for detector cross sections; common standardization of the detector nuclear data used in both fields; the setting up of a common (or compatible) multigroup structure and library applicable to shielding, dosimetry and core physics; the exchange of information and experience in the fields of cross section errors, correlations and adjustment; and the intercomparison of experimental techniques

  10. Minimizing exposure in nuclear medicine through optimum use of shielding devices

    International Nuclear Information System (INIS)

    Rutherford, B.L.; King, S.H.; Erdman, M.C.; Miller, K.L.

    1991-01-01

    Exposure to radiation from nuclear medicine nuclides can be minimized through the use of various shielding devices. This paper reviews the dose reductions achieved through use of various syringe shields, lead aprons, leaded gloves, and several types of eyeglass lenses for 67 Ga, 99m Tc, 131 I and 201 Tl. The authors have found that combination of devices can best provide for minimizing doses

  11. Re-evaluation of structural shielding designs of X-ray and CO-60 gamma-ray scanners at the Port of Tema, Ghana

    International Nuclear Information System (INIS)

    Ofori, K.

    2011-07-01

    This research work was conducted to re-evaluate the shielding designs of the 6 MeV x-ray and the 1.253 MeV Co-60 gamma ray scanners used for cargo-containerized scanning at the Port of Tema. These scanners utilize ionizing radiation, therefore adequate shielding must be provided to reduce the radiation exposure of persons in and around the facilities to acceptable levels. The purpose of radiation shielding is to protect workers and the general public from the harmful effects of ionizing radiation. Investigations on the facilities indicated that after commissioning, no work had been carried out to re-evaluate the shielding designs. However, workloads have increased over time neccessitating review of the installed shielding. There has been introduction of scanner units with higher radiation energy (as in the case of the x-ray scanner) posibily increasing dose rates at various location requiring review of the shielding. New structures have been dotted around the facilities without particular attention to their distances and locations with respect to the radiation source. Measurements of distances from the source axes to the points of concern for primary and leakage barrier shielding; source to container and container to the points of concern for scattered radiation shielding were taken. The primary and secondary thicknesses required for both scanners were determined based on current operational parameters and compared with the thickness constituted during the construction of the facilities. Calculated and measured dose rate beyond the shielding barriers were used to established the adequacy or otherwise of the shielding employed by the shielding designers. Values obtained fell below the 20 µSv/hr specified by NCRP 151 (2005) which showed that the primary and secondary shields of both facilities were adequate requiring no additional shielding. (author)

  12. The use of steel and lead shieldings in radiotherapy rooms and its comparison with respect to neutrons doses at patients; Comparacao de blindagens de aco e de chumbo usadas em salas de radioterapia quanto a dose devido a neutrons depositada em pacientes

    Energy Technology Data Exchange (ETDEWEB)

    Silva, M.G.; Rebello, W.F.; Andrade, E.R.; Medeiros, M.P.C.; Mendes, R.M.S.; Braga, K.L.; Gomes, R.G., E-mail: maglosilva15@gmail.com, E-mail: rebello@ime.eb.br, E-mail: fisica.dna@gmail.com, E-mail: eng.cavaliere@gmail.com, E-mail: raphaelmsm@gmail.com, E-mail: kelmo.lins@gmail.com, E-mail: ggrprojetos@gmail.com [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil); Santos, R.F.G., E-mail: raphaelfgsantos@gmail.com [Centro Universitario Anhanguera, Niteroi, RJ (Brazil). Departamento de Engenharia; Silva, Ademir X., E-mail: ademir@con.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    The NCRP Report No. 151, Structural Shielding Design and Evaluation for Megavoltage X- and Gamma-Ray Radiotherapy Facilities, considers, in shielding calculations for radiotherapy rooms, the use of lead and/or steel to be applied on bunker walls. The NCRP Report calculations were performed foreseeing a better protection of people outside the radiotherapy room. However, contribution of lead and steel to patient dose should be taken into account for radioprotection purposes. This work presents calculations performed by MCNPX code in analyzing the Ambient Dose Equivalent due to neutron, H*(10){sub n}, within a radiotherapy room, in the patients area, considering the use of additional shielding of 1 TVL of lead or 1 TVL of steel, positioned at the inner faces of walls and ceiling of a bunker. The head of the linear accelerator Varian 2100/2300 C/D was modeled working at 18MeV, with 5x5cm{sup 2}, 10x10cm{sup 2}, 20x20cm{sup 2}, 30x30cm{sup 2} and 40x40cm{sup 2} openings for jaws and MLC and operating in eight gantry's angles. This study shows that the use of lead generates an average value of H*(10){sub n} at patients area, 8.02% higher than the expected when using steel. Further studies should be performed based on experimental data for comparison with those from MCNPX simulation.

  13. Efficacy of Breast Shielding During CT of the Head

    International Nuclear Information System (INIS)

    Brnic, Z.; Vekic, B.; Hebrang, A.; Anic, P.

    2003-01-01

    The use of computerized tomography (CT) is rapidly increasing in last two decades, and this method has become the major non-natural source of radiation exposure to the population. CT examinations delivers to the patients more radiation than all other imaging techniques, and contribute disproportionately to the collective dose; in Britain it has been estimated that 4% of diagnostic radiology procedures are CT examinations, being responsible for approximately 40% of the total annual collective dose. Breast doses are high in CT examinations with breasts in scanning planes, being not insignificant also when breasts are exposed only to scatter radiation. Breast doses received through scatter radiation during head CT may account for up to one-fifth of an average mammographic dose per one view. Whilst the possibilities of reduction of radiation load to organs lying in CT scanning planes are limited, the tissues outside the primary beam should be protected against scatter whenever it does not sacrifice image quality. Lead shielding results in significant reduction of external scatter to radiosensitive superficial organs in many diagnostic procedures. The published studies of breast shielding against scatter radiation in diagnostic radiology are scanty, only the later one dealing particularly with breast shielding during head CT examination. The aims of this study were to investigate in vivo the levels of breast exposure to scatter radiation in head CT examination and the dependence of breast exposure upon body constitution. We tried to estimate the efficacy of external lead shielding as a mean of breast dose reduction, and to determine how much radiation reaches the organ from outside, in comparison to radiation load caused through internal scatter. We conclude that, although the level of breast radiation exposure during head CT examinations is generally low, shielding of the breasts with lead apron will further reduce the doses. However is the effect of shielding limited

  14. A novel comprehensive utilization of vanadium slag: As gamma ray shielding material

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Mengge [School of Metallurgy, Northeastern University, Shenyang 110004 (China); Liaoning Key Laboratory of Metallurgical Resources Recycling Science, Shenyang 110004 (China); Xue, Xiangxin, E-mail: xuexx@mail.neu.edu.cn [School of Metallurgy, Northeastern University, Shenyang 110004 (China); Liaoning Key Laboratory of Metallurgical Resources Recycling Science, Shenyang 110004 (China); Yang, He; Liu, Dong [School of Metallurgy, Northeastern University, Shenyang 110004 (China); Liaoning Key Laboratory of Metallurgical Resources Recycling Science, Shenyang 110004 (China); Wang, Chao [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Li, Zhefu [Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2016-11-15

    Highlights: • A novel comprehensive utilization method for vanadium slag is proposed. • Shielding properties of vanadium slag are better than ordinary concrete. • HVL of vanadium slag is between Lead and concrete to shield {sup 60}Co gamma ray. • HVL of composite is higher than concrete when adding amount of vanadium slag is 900. • Composite can be used as injecting mortar for cracks developed in concrete shields. - Abstract: New exploration of vanadium slag as gamma ray shielding material was proposed, the shielding properties of vanadium slag was higher than concrete when the energy of photons was in 0.0001 MeV–100000 MeV. Vanadium slag/epoxy resin composites were prepared, shielding and material properties of materials were tested by {sup 60}Co gamma ray, simultaneous DSC-TGA, electronic universal testing machine and scanning electron microscopy, respectively. The results showed that the shielding properties of composite would be better with the increase of vanadium slag addition amount. The HVL (half value layer thickness) of vanadium slag was between Lead and concrete while composite was higher than concrete when the addition amount of vanadium slag was 900 used as material to shield {sup 60}Co gamma ray, also the resistance temperature of composite was about 215 °C and the bending strength was over 10 MPa. The composites could be used as injecting mortar for cracks developed in biological concrete shields, coating for the floor of the nuclear facilities, and shielding materials by itself.

  15. Shielding plugs

    International Nuclear Information System (INIS)

    Makishima, Kenji.

    1986-01-01

    Purpose: In shielding plugs of an LMFBR type reactor, to restrain natural convection of heat in an annular space between a thermal shield layer and a shield shell, to prevent the lowering of heat-insulation performance, and to alleviate a thermal stress in a reactor container and the shield shell. Constitution: A ring-like leaf spring split in the direction of height is disposed in an annular space between a thermal shield layer and a shield shell. In consequence, the space is partitioned in the direction of height and, therefore, if axial temperature conditions and space width are the same and the space is low, the natural convection is hard to occur. Thus the rise of upper surface temperature of the shielding plugs can prevent the lowering of the heat insulation performance which will result in the increment of shielding plug cooling capacity, thereby improving reliability. In the meantime, since there is mounted an earthquake-resisting support, the thermal shield layer will move for a slight gap in case of an earthquake, being supported by the earthquake-resisting support, and the movement of the thermal shield layer is restricted, thereby maintaining integrity without increasing the stroke of the ring-like spring. (Kawakami, Y.)

  16. Electrically nonconductive shield for electric equipment generating ionizing radiation

    International Nuclear Information System (INIS)

    Aitken, D.

    1979-01-01

    As a radiation protection shield there is proposed a nonconductive shield fabricated from epoxides or other plastics material and containing finely dispersed radiation absorbing metal. It is to be designed in such a way that it lies in the range of a high electric gradient in the equipment, close to the radiation-producing component. As suitable metals there are mentioned tin, tungsten, and lead resp. their oxides. As an example there is used an X-ray shielding. (RW) 891 RW/RW 892 MKO [de

  17. System for detecting and processing abnormality in electromagnetic shielding

    International Nuclear Information System (INIS)

    Takahashi, T.; Nakamura, M.; Yabana, Y.; Ishikawa, T.; Nagata, K.

    1991-01-01

    The present invention relates to a system for detecting and processing an abnormality in electromagnetic shielding of an intelligent building which is constructed using an electromagnetic shielding material for the skeleton and openings such as windows and doorways so that the whole of the building is formed into an electromagnetic shielding structure. (author). 4 figs

  18. Monte Carlo simulations and measurements for efficiency determination of lead shielded plastic scintillator detectors

    Science.gov (United States)

    Yasin, Zafar; Negoita, Florin; Tabbassum, Sana; Borcea, Ruxandra; Kisyov, Stanimir

    2017-12-01

    The plastic scintillators are used in different areas of science and technology. One of the use of these scintillator detectors is as beam loss monitors (BLM) for new generation of high intensity heavy ion in superconducting linear accelerators. Operated in pulse counting mode with rather high thresholds and shielded by few centimeters of lead in order to cope with radiofrequency noise and X-ray background emitted by accelerator cavities, they preserve high efficiency for high energy gamma ray and neutrons produced in the nuclear reactions of lost beam particles with accelerator components. Efficiency calculation and calibration of detectors is very important before their practical usage. In the present work, the efficiency of plastic scintillator detectors is simulated using FLUKA for different gamma and neutron sources like, 60Co, 137Cs and 238Pu-Be. The sources are placed at different positions around the detector. Calculated values are compared with the measured values and a reasonable agreement is observed.

  19. Designing shields for KeV photons with genetic algorithms

    International Nuclear Information System (INIS)

    Asbury, Stephen; Holloway, James P.

    2011-01-01

    Shielding of x-ray sources and low energy gamma rays is often accomplished with lead aprons, comprising a thin layer (0.5 mm to 1 mm) of lead or similar high-Z material. In previous work the authors used Genetic Algorithms to explore the design of a shadow shield for space applications. Now those techniques have been applied to the problem of shielding humans from low energy gamma radiation. This paper uses a simple geometry to explore layering various materials as a method to reduce mass and dose for thin gamma shields. The genetic algorithms discover layers of materials with various Z is in fact more effective than an equivalent mass of Pb alone for lower energy gammas, but as the incident radiation energy increases the efficacy of such layering diminishes. The utility of varying Z for lower energy gammas is in part due to their complementary K-edges, where one material compensates for the transmission that would occur just below the K-edge in another material. (author)

  20. A method for assessing the structural shielding in diagnostic x-ray facilities

    International Nuclear Information System (INIS)

    Almeida, F.; Martinez de la Fuente, O.; Perez, C.

    1992-01-01

    The design of each X-Ray medical facility involves, in order to guarantee the optimun levels of Radiologic safety for everybody who could be exposed during the performance of the examinations the need of assessing the required shieldings for the room which contains the emiter tubes. In such sense, this paper gives a number of criteria to calculate the structural requirements for the diverse configurations which exist in Health Centres using the method proposed by NCRP in its Report 49 as a reference. (author)

  1. Radiation dose reduction at a price: the effectiveness of a thyroid shield during head CT scanning

    International Nuclear Information System (INIS)

    Fu Qiang; Lu Tao; Zhang Ling

    2008-01-01

    Objective: To assess radiation dose to the thyroid in patients undergoing head CT scanning and to evaluate dose reduction to the thyroid by load shielding. Methods: A post-morterm was scanned by different model and study was undertaken to evaluate the dose reduction by thyroid lead shields and assess their practicality in a clinical setting. (a)No thyroid shields and (b) thyroid shield. One thermoluminescent dosimeters (TLDs)were placed over the thyroid gland center, A thyroid lead shield (Pb eq 0.5mm)was placed around the neck of post-morterm. Scan parameter, CTDIw and DLP were recorded. Results: (a) 0.207mSv; (b) 0.085mSv. A mean effective radiation dose reduction of 58% was seen in the shielded versus the unshielded. Conclusion: Thyroid exposure to scattered radiation from head CT scanning only once is associated with a low but not negligible risk of cancer, but accumulatived doses to the thyroid are serious, highlighting the need for increased awareness of patient radiation protection. Thyroid lead shielding yields significant radiation protection, which should be used routinely during head CT scan. (authors)

  2. Thermal shield support degradation in pressurized water reactors

    International Nuclear Information System (INIS)

    Sweeney, F.J.; Fry, D.N.

    1986-01-01

    Damage to the thermal shield support structures of three pressurized water reactors (PWRs) due to flow-induced vibrations was recently discovered during refueling. In two of the reactors, severe damage occurred to the thermal shield, and in one reactor the core support barrel (CSB) was damaged, necessitating extended outages for repairs. In all three reactors, several of the thermal shield supports were either loose, damaged, or missing. The three plants had been in operation for approximately 10 years before the damage was apparent by visual inspection. Because each of the three US PWR manufacturers have experienced thermal shield support degradation, the Nuclear Regulatory Commission requested that Oak Ridge National Laboratory analyze ex-core neutron detector noise data to determine the feasibility of detecting incipient thermal shield support degradation. Results of the noise data analysis indicate that thermal shield support degradation probably began early in the life of both severely damaged plants. The degradation was characterized by shifts in the resonant frequencies of core internal structures and the appearance of new resonances in the ex-core neutron detector noise. Both the data analyses and the finite element calculations indicate that these changes in resonant frequencies are less than 3 Hz. 11 refs., 16 figs

  3. Indicia carbonate - ultrabasic massives of Ukrainian Shield

    Directory of Open Access Journals (Sweden)

    Popovchenko S.E.

    2014-12-01

    Full Text Available Researches of geology and composition of silicate-carbonate rocks of the Ukrainian shield. Concluded that they belonged to the karbonatites of the normal series. Metallogenic characteristics and specialization are confirming to the magmatic origin and resemblance with karbonatites alkaline series. In connection with the prevalence in the Precambrian ultrabasic-basic formation of carbonatites magmatism it was, seems to be more widespread in the areal extent of the ancient protoplatforms and rift zones. Numerous experimental data explicitly confirm the possibility of origin of dolomite melts of peridotite magma at its saturation pressure of CO2 and more than 5.7 GPa. Determined formational belonging and potential metallogenic specialization of silicate-carbonate rocks, associated with ultrabasic complexes of the Ukrainian Shield. Particular attention is paid to the identification of features that silicate-carbonate rocks can be attributed to magmatic or metamorphogenic-sedimentary formations, compared to their material composition and geotectonic position. As a result, identified the main characteristics for their recognition. Of these, the leading classified geotectonic, structural-geological, petrographic and mineralogical features, material composition and structure of the silicate-carbonate rocks associated with them relations of ultrabasic, mineralogical and geochemical features and communication with the manifestations useful mineralization. When you select features also include the effect of metamorphism on the nature of the transformation of carbonate-ultrabasic massifs and their modern look at this level erosion of the crust.

  4. Cosmic Ray Interactions in Shielding Materials

    International Nuclear Information System (INIS)

    Aguayo Navarrete, Estanislao; Kouzes, Richard T.; Ankney, Austin S.; Orrell, John L.; Berguson, Timothy J.; Troy, Meredith D.

    2011-01-01

    This document provides a detailed study of materials used to shield against the hadronic particles from cosmic ray showers at Earth's surface. This work was motivated by the need for a shield that minimizes activation of the enriched germanium during transport for the MAJORANA collaboration. The materials suitable for cosmic-ray shield design are materials such as lead and iron that will stop the primary protons, and materials like polyethylene, borated polyethylene, concrete and water that will stop the induced neutrons. The interaction of the different cosmic-ray components at ground level (protons, neutrons, muons) with their wide energy range (from kilo-electron volts to giga-electron volts) is a complex calculation. Monte Carlo calculations have proven to be a suitable tool for the simulation of nucleon transport, including hadron interactions and radioactive isotope production. The industry standard Monte Carlo simulation tool, Geant4, was used for this study. The result of this study is the assertion that activation at Earth's surface is a result of the neutronic and protonic components of the cosmic-ray shower. The best material to shield against these cosmic-ray components is iron, which has the best combination of primary shielding and minimal secondary neutron production.

  5. Mechanical design of the TIBER breeding shield

    Energy Technology Data Exchange (ETDEWEB)

    Rathke, J.; Deutsch, L. (Grumman Corp., Bethpage, NY (USA). Space Systems Div.)

    1989-04-01

    TIBER features a segmented shield assembly that provides the nuclear shielding for the superconducting toroidal field coils. In addition to its primary function, the shield also provides tritium breeding through the use of water coolant that contains 16 wt% dissolved lithium nitrate. Because the TIBER reactor need not provide electrical power, the coolant is maintained at low pressure (0.2 MPa) and low temperature (75/sup 0/C). The shield is made in several segments to facilitate assembly and allow for replacement of high heat flux components (divertor blades). The segments are designated as inboard, outboard, upper, lower, and divertor modules. In total, there are 96 separate modules in the machine, consisting of six different types. The design features of the different modules vary primarily depending on the thickness of the shield in a given location. The very thick outboard shield has a breeding zone in the inboard portion of the module, with a shielding zone behind it. The breeding zone consists of a stainless steel casing filled with beryllium spheres. The shielding zone consists of the same casing filled with steel spheres. Both of these zones have lithiated water circulated throughout to provide cooling and breeding. In zones with minimal thickness, tungsten alloys are used to achieve the required shielding. These alloys are incoprorated in subassemblies utilizing stainless steel casings surrounding blocks of tungsten heavy metal alloy. These are infiltrated with lead on final assembly to form a thermally continuous panel. Several of these panels are then assembled into an outer stainless steel case to form an inboard module. These modules also use the lithiated coolant. The details of the design are presented and discussed. (orig.).

  6. Identification of Shielding Material Configurations Using NMIS Imaging

    International Nuclear Information System (INIS)

    Grogan, Brandon R.; Mihalczo, John T.; McConchie, Seth M.; Mullens, James Allen

    2011-01-01

    The Nuclear Materials Identification System (NMIS) uses fast neutron tomographic imaging to nonintrusively examine the interior structure of shielded objects. The pixel values in such images represent the attenuation coefficients of the time- and directionally-tagged fast neutrons from a deuterium-tritium (D T) neutron generator. The reconstruction techniques use either a filtered back projection or a maximum likelihood expectation maximization algorithm. As a first test of the capabilities of these reconstruction techniques to correctly identify individual parts inside of an object, fast neutron imaging was used to identify the regions of shielding surrounding a depleted uranium casting from a library of possible parts. The shielding consisted of multiple regions of common materials such as steel, lead, aluminum, and polyethylene. First, the full object was imaged, and then each of the individual parts was imaged. Several additional parts that were not present in the original object were also imaged to form a library. The individual parts were compared to the full object, and the correct ones were identified using three different methods. These methods included a visual match, an iterative fit of each part, and a mathematical test comparing the sum of squared errors. The successful results demonstrate an initial application of matching. This suggests that it should be possible to implement more sophisticated matching techniques using automated pixel-by-pixel comparison methods in the future.

  7. Applications to shielding design and others of monte carlo method

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Daiichiro [Mitsui Engineering and Shipbuiding Co., Ltd., Tokyo (Japan)

    2001-01-01

    One-dimensional or two-dimensional Sn computer code (ANISN, DOT3.5, etc.) and a point attenuation kernel integral code (QAD, etc.) have been used widely for shielding design. Application examples of monte carlo method which could follow precisely the three-dimensional configuration of shielding structure are shown as follow: (1) CASTER cask has a complex structure which consists of a large number of fuel baskets (stainless steel), neutron moderators (polyethylene rods), the body (cast iron), and cooling fin. The R-{theta} model of Sn code DOT3.5 cannot follow closely the complex form of polyethylene rods and fuel baskets. A monte carlo code MORSE is used to ascertain the calculation results of DOT3.5. The discrepancy between the calculation results of DOT3.5 and MORSE was in 10% for dose rate at distance of 1 m from the cask surface. (2) The dose rates of an iron cell at 10 cm above the floor are calculated by the code QAD and the MORSE. The reflected components of gamma ray caused by the auxiliary floor shield (lead) are analyzed by the MORSE. (3) A monte carlo code MCNP4A is used for skyshine evaluation of spent fuel carrier ship 'ROKUEIMARU'. The direct and skyshine components of gamma ray and neutron flux are estimated at each center of engine room and wheel house. The skyshine dose rate of neutron flux is 5-15 times larger than the gamma ray. (M. Suetake)

  8. Radiation shielding material

    International Nuclear Information System (INIS)

    Kawakubo, Takamasa; Yamada, Fumiyuki; Nakazato, Kenjiro.

    1976-01-01

    Purpose: To provide a material, which is used for printing a samples name and date on an X-ray photographic film at the same time an X-ray radiography. Constitution: A radiation shielding material of a large mass absorption coefficient such as lead oxide, barium oxide, barium sulfate, etc. is added to a solution of a radiation permeable substance capable of imparting cold plastic fluidity (such as microcrystalline wax, paraffin, low molecular polyethylene, polyvinyl chloride, etc.). The resultant system is agitated and then cooled, and thereafter it is press fitted to or bonded to a base in the form of a film of a predetermined thickness. This radiation shielding layer is scraped off by using a writing tool to enter information to be printed in a photographic film, and then it is laid over the film and exposed to X-radiation to thereby print the information on the film. (Seki, T.)

  9. Structure shielding from cloud and fallout gamma ray sources for assessing the consequences of reactor accidents

    International Nuclear Information System (INIS)

    Burson, Z.G.; Profio, A.E.

    1975-12-01

    Radiation shielding provided by transportation vehicles and structures typical of where people live and work were estimated for cloud and fallout gamma-ray sources resulting from a hypothetical reactor accident. Dose reduction factors are recommended for a variety of situations for realistically assessing the consequences of reactor accidents

  10. Radiation protection of staff in 111In radionuclide therapy--is the lead apron shielding effective?

    Science.gov (United States)

    Lyra, M; Charalambatou, P; Sotiropoulos, M; Diamantopoulos, S

    2011-09-01

    (111)In (Eγ = 171-245 keV, t1/2 = 2.83 d) is used for targeted therapies of endocrine tumours. An average activity of 6.3 GBq is injected into the liver by catheterisation of the hepatic artery. This procedure is time-consuming (4-5 min) and as a result, both the physicians and the technical staff involved are subjected to radiation exposure. In this research, the efficiency of the use of lead apron has been studied as far as the radiation protection of the working staff is concerned. A solution of (111)In in a cylindrical scattering phantom was used as a source. Close to the scattering phantom, an anthropomorphic male Alderson RANDO phantom was positioned. Thermoluminescent dosemeters were located in triplets on the front surface, in the exit and in various depths in the 26th slice of the RANDO phantom. The experiment was repeated by covering the RANDO phantom by a lead apron 0.25 mm Pb equivalent. The unshielded dose rates and the shielded photon dose rates were measured. Calculations of dose rates by Monte Carlo N-particle transport code were compared with this study's measurements. A significant reduction of 65 % on surface dose was observed when using lead apron. A decrease of 30 % in the mean absorbed dose among the different depths of the 26th slice of the RANDO phantom has also been noticed. An accurate correlation of the experimental results with Monte Carlo simulation has been achieved.

  11. Radiation protection of staff in 111In radionuclide therapy-Is the lead apron shielding effective?

    International Nuclear Information System (INIS)

    Lyra, M.; Charalambatou, P.; Sotiropoulos, M.; Diamantopoulos, S.

    2011-01-01

    111 In (Eγ=171-245 keV, t1/2=2.83 d) is used for targeted therapies of endocrine tumours. An average activity of 6.3 GBq is injected into the liver by catheterisation of the hepatic artery. This procedure is time-consuming (4-5 min) and as a result, both the physicians and the technical staff involved are subjected to radiation exposure. In this research, the efficiency of the use of lead apron has been studied as far as the radiation protection of the working staff is concerned. A solution of 111 In in a cylindrical scattering phantom was used as a source. Close to the scattering phantom, an anthropomorphic male Alderson RANDO phantom was positioned. Thermoluminescent dosemeters were located in triplets on the front surface, in the exit and in various depths in the 26. slice of the RANDO phantom. The experiment was repeated by covering the RANDO phantom by a lead apron 0.25 mm Pb equivalent. The unshielded dose rates and the shielded photon dose rates were measured. Calculations of dose rates by Monte Carlo N-particle transport code were compared with this study's measurements. A significant reduction of 65 % on surface dose was observed when using lead apron. A decrease of 30 % in the mean absorbed dose among the different depths of the 26. slice of the RANDO phantom has also been noticed. An accurate correlation of the experimental results with Monte Carlo simulation has been achieved. (authors)

  12. Significant reduction of radiation exposure to operator and staff during cardiac interventions by analysis of radiation leakage and improved lead shielding.

    Science.gov (United States)

    Kuon, Eberhard; Schmitt, Moritz; Dahm, Johannes B

    2002-01-01

    The objectives of this study were to disclose and to reduce occupational radiation leakage in invasive cardiology. Prospectively, we analyzed various dose parameters for 330 coronary procedures. We used a Rando phantom to measure scatter entrance skin air kerma to the operator (S-ESAK-O) during fluoroscopy for all standard tube angulations, and to plot isodose lines for 0 degrees /0 degrees -posterior anterior angulation. The patient's measured dose area product due to diagnostic catheterization and elective percutaneous transluminal coronary angioplasty was 6.2 and 10.4 Gycm(2), which represents 11% and 13% of currently typical values, respectively. With use of 0.5- and 1.0-mm overcouch and undercouch shielding, it was possible to reduce the mean of 4,686 nSv/Gycm(2) to 677 and 277 nSv/Gycm(2), respectively. Closure of radiation leakage up to 897 microSv/hour at the operator's gonadal height (80 to 105 cm), not heretofore described, was achieved by an additional 1.0-mm, lead-equivalent undercouch-top and overcouch-flap adjacent to the table, down to a S-ESAK-O/dose area product level of 47.5 nSv/Gycm(2). With use of a 0.5-mm lead apron, collar, glasses, foot-switch shield and 1.0-mm lead cover around the patient's thighs, the operator received a mean S-ESAK-O of 8.5, while his forehead, eyes, thyroid, chest, gonads, and hands were exposed to 68.2, 1.2, 1.2, 1.2, 0.8, and 58.2 nSv/Gycm(2), respectively. In conclusion, radiation-attenuating intervention techniques and improved lead protection can effectively contribute to a new state of the art in invasive cardiology, with reduction of operator radiation exposure to 0.8% of typical S-ESAK-O levels in advanced catheterization laboratories.

  13. Nuclear reactor shield including magnesium oxide

    International Nuclear Information System (INIS)

    Rouse, C.A.; Simnad, M.T.

    1981-01-01

    An improvement is described for nuclear reactor shielding of a type used in reactor applications involving significant amounts of fast neutron flux. The reactor shielding includes means providing structural support, neutron moderator material, neutron absorber material and other components, wherein at least a portion of the neutron moderator material is magnesium in the form of magnesium oxide either alone or in combination with other moderator materials such as graphite and iron

  14. Active Radiation Shield, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — DEC-Shield technology offers the means to generate electric power from cosmic radiation sources and fuse dissimilar systems and functionality into a structural...

  15. Detector Background Reduction by Passive and Active Shielding

    International Nuclear Information System (INIS)

    Bikit, I.; Bikit, K.; Forkapic, S.; Mrda, D.; Nikolov, J.; Slivka, J.; Todorovic, N.

    2013-01-01

    The operational problems of the gamma ray spectrometer shielded passively with 12 cm of lead and actively by five 0.5 m × 0.5 m × 0.05 m plastic veto shields are described. The active shielding effect from both environmental gamma ray, cosmic muons and neutrons was investigated. For anticoincidence gating wide range of scintillator pulses, corresponding to the energy range of 150 keV-75 MeV, were used. With the optimal set up the integral background, for the energy region of 50 - 3000 keV, of 0.31 c/s was achieved. The detector mass related background was 0.345 c/(kg s). The 511 keV annihilation line was reduced by the factor of 7 by the anticoincidence gate. It is shown that the plastic shields increase the neutron capture gamma line intensities due to neutron termalization.(author)

  16. Neutron shield analysis and design for the PDX fusion facility

    International Nuclear Information System (INIS)

    Grimesey, R.A.; Nigg, D.W.; Scott, A.J.; Wheeler, F.J.; Jassby, D.L.; Perry, E.D.

    1979-01-01

    The basic component of the biological shield for PDX is an existing 81 cm thick high-density concrete shielding wall surrounding the machine. The principal additional shielding requirement is a roof shield over the machine to reduce air-scattered skyshine dose into the PDX control room and to the site boundary. The roof shield is designed in removable sections on a steel support structure permitting overhead crane access to major PDX components. After analysis of a number of alternate concepts, a roof shield consisting of 50 cm of water in polyethylene tanks was selected to meet design objectives of effectiveness, weight, removability, and cost

  17. Optimal selection for shielding materials by fuzzy linear programming

    International Nuclear Information System (INIS)

    Kanai, Y.; Miura, N.; Sugasawa, S.

    1996-01-01

    An application of fuzzy linear programming methods to optimization of a radiation shield is presented. The main purpose of the present study is the choice of materials and the search of the ratio of mixture-component as the first stage of the methodology on optimum shielding design according to individual requirements of nuclear reactor, reprocessing facility, shipping cask installing spent fuel, ect. The characteristic values for the shield optimization may be considered their cost, spatial space, weight and some shielding qualities such as activation rate and total dose rate for neutron and gamma ray (includes secondary gamma ray). This new approach can reduce huge combination calculations for conventional two-valued logic approaches to representative single shielding calculation by group-wised optimization parameters determined in advance. Using the fuzzy linear programming method, possibilities for reducing radiation effects attainable in optimal compositions hydrated, lead- and boron-contained materials are investigated

  18. Survivor shielding. Part A. Nagasaki factory worker shielding

    International Nuclear Information System (INIS)

    Santoro, Robert T.; Barnes, John M.; Azmy, Yousry Y.; Kerr, George D.; Egbert, Stephen D.; Cullings, Harry M.

    2005-01-01

    Recent investigations based on conventional chromosome aberration data by the RERF suggest that the DS86 doses received by many Nagasaki factory workers may have been overestimated by as much as 40% relative to those for other survivors in Japanese-type houses and other shielding configurations (Kodama et al. 2001). Since the factory workers represent about 25% of the Nagasaki survivors with DS86 doses in excess of 0.5 Gy (50 rad), systematic errors in their dose estimates can have a major impact on the risk coefficients from RERF studies. The factory worker doses may have been overestimated for a number of reasons. The calculation techniques, including the factory building modeling, weapon source spectra and cross-section data used in the DS86 shielding calculations were not detailed enough to replicate actual conditions. The models used did not take into account local shielding provided by machinery, tools, and the internal structure in the buildings. In addition, changes in the disposition of shielding following collapse of the building by the blast wave were not considered. The location of large factory complexes may be uncertain, causing large numbers of factory survivors, correctly located relative to each other, to be uniformly too close to the hypocenter. Any or all of these reasons are sufficient to result in an overestimate of the factory worker doses. During the DS02 studies, factory worker doses have been reassessed by more carefully modeling the factory buildings, incorporating improved radiation transport methods and cross-section data and using the most recent bomb leakage spectra (Chapter 2). Two-dimensional discrete ordinates calculations were carried out initially to estimate the effects of workbenches and tools on worker doses to determine if the inclusion of these components would, in fact, reduce the dose by amounts consistent with the RERF observations (Kodama et al. 2001). (author)

  19. A conceptual gamma shield design using the DRP model computation

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, E E [Reactor Department, Nuclear Research Center, Atomic Energy Authority, Cairo (Egypt); Rahman, F A [National Center of Nuclear Safety and Radiation Control, Atomic Energy Authority, Cairo (Egypt)

    1997-12-31

    The purpose of this investigation is to assess basic areas of concern in the development of reactor shielding conceptual design calculations. A spherical shield model composed of low carbon steel and lead have been constructed to surround a Co-60 gamma point source. two alternative configurations have been considered in the model computation. The numerical calculations have been performed using both the ANISN code and DRP model computation together with the DLC 75-Bugle 80 data library. A resume of results for deep penetration in different shield materials with different packing densities is presented and analysed. The results showed that the gamma fluxes attenuation is increased with increasing distribution the packing density of the shield material which reflects its importance of considering it as a safety parameter in shielding design. 3 figs.

  20. Safety and Health Topics: Lead

    Science.gov (United States)

    ... ammunition, pipes, cable covering, building material, solder, radiation shielding, collapsible tubes, and fishing weights. Lead is also ... lead linings in tanks and radiation protection, leaded glass, work involving soldering, and other work involving lead ...

  1. Protein surface shielding agents in protein crystallization

    International Nuclear Information System (INIS)

    Hašek, J.

    2011-01-01

    The crystallization process can be controlled by protein surface shielding agents blocking undesirable competitive adhesion modes during non-equilibrium processes of deposition of protein molecules on the surface of growing crystalline blocks. The hypothesis is based on a number of experimental proofs from diffraction experiments and also retrieved from the Protein Data Bank. The molecules adhering temporarily on the surface of protein molecules change the propensity of protein molecules to deposit on the crystal surface in a definite position and orientation. The concepts of competitive adhesion modes and protein surface shielding agents acting on the surface of molecules in a non-equilibrium process of protein crystallization provide a useful platform for the control of crystallization. The desirable goal, i.e. a transient preference of a single dominating adhesion mode between protein molecules during crystallization, leads to uniform deposition of proteins in a crystal. This condition is the most important factor for diffraction quality and thus also for the accuracy of protein structure determination. The presented hypothesis is a generalization of the experimentally well proven behaviour of hydrophilic polymers on the surface of protein molecules of other compounds

  2. Design of radiation shields in nuclear reactor core

    International Nuclear Information System (INIS)

    Mousavi Shirazi, A.; Daneshvar, Sh.; Aghanajafi, C.; Jahanfarnia, Gh.; Rahgoshay, M.

    2008-01-01

    This article consists of designing radiation shields in the core of nuclear reactors to control and restrain the harmful nuclear radiations in the nuclear reactor cores. The radiation shields protect the loss of energy. caused by nuclear radiation in a nuclear reactor core and consequently, they cause to increase the efficiency of the reactor and decrease the risk of being under harmful radiations for the staff. In order to design these shields, by making advantages of the O ppenheim Electrical Network m ethod, the structure of the shields are physically simulated and by obtaining a special algorithm, the amount of optimized energy caused by nuclear radiations, is calculated

  3. Photonic Bandgap (PBG) Shielding Technology

    Science.gov (United States)

    Bastin, Gary L.

    2007-01-01

    Photonic Bandgap (PBG) shielding technology is a new approach to designing electromagnetic shielding materials for mitigating Electromagnetic Interference (EM!) with small, light-weight shielding materials. It focuses on ground planes of printed wiring boards (PWBs), rather than on components. Modem PSG materials also are emerging based on planar materials, in place of earlier, bulkier, 3-dimensional PBG structures. Planar PBG designs especially show great promise in mitigating and suppressing EMI and crosstalk for aerospace designs, such as needed for NASA's Constellation Program, for returning humans to the moon and for use by our first human visitors traveling to and from Mars. Photonic Bandgap (PBG) materials are also known as artificial dielectrics, meta-materials, and photonic crystals. General PBG materials are fundamentally periodic slow-wave structures in I, 2, or 3 dimensions. By adjusting the choice of structure periodicities in terms of size and recurring structure spacings, multiple scatterings of surface waves can be created that act as a forbidden energy gap (i.e., a range of frequencies) over which nominally-conductive metallic conductors cease to be a conductor and become dielectrics. Equivalently, PBG materials can be regarded as giving rise to forbidden energy gaps in metals without chemical doping, analogous to electron bandgap properties that previously gave rise to the modem semiconductor industry 60 years ago. Electromagnetic waves cannot propagate over bandgap regions that are created with PBG materials, that is, over frequencies for which a bandgap is artificially created through introducing periodic defects

  4. Application of gypsum as shielding against low-energy X-radiation in the radiodiagnosis area

    International Nuclear Information System (INIS)

    Lins, J.A.G.; Lima, F.R.A.; Santos, M.A.P. dos; Oliveira, D.N.S. de; Silva, V.H.F.F. da

    2017-01-01

    In recent years, materials such as lead, concrete and iron have been studied for use as shielding for ionizing radiations of different energies in radiative installations. In the radiodiagnosis area, lead and barite are the most used materials as shielding. However, for beams of low energy X-radiation, such as in mammography and dentistry, the gypsum material may be used. This study aims to verify the feasibility of the use of gypsum as shielding for low-energy X-ray using standardized dental X-ray beams in a metrology laboratory. The project will allow a better understanding in the study of gypsum used as shielding, certifying its use as a good attenuator for low-energy X-ray

  5. Status of the ITER tokamak nuclear shielding and radiological protection design

    Energy Technology Data Exchange (ETDEWEB)

    Leichtle, D., E-mail: dieter.leichtle@f4e.europa.eu [Fusion for Energy, Josep Pla 2, Barcelona 08019 (Spain); Chaffard, P.Y.; Izquierdo, J. [Fusion for Energy, Josep Pla 2, Barcelona 08019 (Spain); Juarez, R. [UNED, Juan del Rosal 12, Madrid 28040 (Spain); Pampin, R.; Portone, A. [Fusion for Energy, Josep Pla 2, Barcelona 08019 (Spain)

    2016-11-01

    Highlights: • Comprehensive review of design status of the ITER tokamak regarding nuclear shielding. • Investigation of shield design options and streaming mitigation measures. • Review of state-of-the-art shutdown dose rate analyses for selected port systems. - Abstract: Nuclear shielding of the ITER tokamak encompasses several systems and interfaces in a complex radiation environment. Therefore any shielding design has to involve a series of structures, systems and components in an integrated approach. This is evident for the complex ex-vessel radiation environment with streaming and leakage of plasma neutrons and subsequent activation of ex-vessel structures which give raise to excessive shutdown dose rates in accessible areas of the cryostat. The paper reviews recent nuclear analyses related to the performance of primary shields and highlights challenges toward an integrated nuclear shielding design. The general need of propagation of shielding requirements is highlighted in the context of radiation cross talk due to penetrations. Radiation streaming through gaps and penetrations is a key problem in any efficient shield design. The impact on the evolving radiation environment due to several design options along streaming paths such as port gaps, as well as their modeling for nuclear analysis, is presented. Implications regarding design integration and compliance with integrated shielding requirements and ALARA dose are finally given.

  6. Design optimization of radiation shielding structure for lead slowing-down spectrometer system

    OpenAIRE

    Kim, Jeong Dong; Ahn, Sangjoon; Lee, Yong Deok; Park, Chang Je

    2015-01-01

    A lead slowing-down spectrometer (LSDS) system is a promising nondestructive assay technique that enables a quantitative measurement of the isotopic contents of major fissile isotopes in spent nuclear fuel and its pyroprocessing counterparts, such as 235U, 239Pu, 241Pu, and, potentially, minor actinides. The LSDS system currently under development at the Korea Atomic Energy Research Institute (Daejeon, Korea) is planned to utilize a high-flux (>1012 n/cm2·s) neutron source comprised of a high...

  7. Assessment of the integrity of structural shielding of four computed tomography facilities in the greater Accra region of Ghana

    International Nuclear Information System (INIS)

    Nkansah, A.; Schandorf, C.; Boadu, M.; Fletcher, J. J.

    2013-01-01

    The structural shielding thicknesses of the walls of four computed tomography (CT) facilities in Ghana were re-evaluated to verify the shielding integrity using the new shielding design methods recommended by the National Council on Radiological Protection and Measurements (NCRP). The shielding thickness obtained ranged from 120 to 155 mm using default DLP values proposed by the European Commission and 110 to 168 mm using derived DLP values from the four CT manufacturers. These values are within the accepted standard concrete wall thickness ranging from 102 to 152 mm prescribed by the NCRP. The ultrasonic pulse testing of all walls indicated that these are of good quality and free of voids since pulse velocities estimated were within the range of 3.496±0.005 km s -1 . An average dose equivalent rate estimated for supervised areas is 3.4±0.27 μSv week -1 and that for the controlled area is 18.0±0.15 μSv week -1 , which are within acceptable values. (authors)

  8. PEP radiation shielding tests in SLAC A Beam

    International Nuclear Information System (INIS)

    Ash, W.; DeStaebler, H.; Harris, J.; Jenkins, T.; Murray, J.

    1977-09-01

    Radiation shielding tests designed to simulate possible conditions in and around the PEP experimental halls were conducted. The SLAC A Beam was targeted in the block tunnel at a point about midway between End Station A and Beam Dump East. At that site it was relatively easy to rearrange the concrete block structure to simulate the various shielding configurations under consideration for PEP. Extensive surveys of neutron and ionizing radiation were made. Complete results of the shielding tests are given

  9. Detection of shielded radionuclides from weak and poorly resolved spectra using group positive RIVAL

    International Nuclear Information System (INIS)

    Kump, Paul; Bai, Er-Wei; Chan, Kung-Sik; Eichinger, William

    2013-01-01

    This paper is concerned with the identification of nuclides from weak and poorly resolved spectra in the presence of unknown radiation shielding materials such as carbon, water, concrete and lead. Since a shield will attenuate lower energies more so than higher ones, isotope sub-spectra must be introduced into models and into detection algorithms. We propose a new algorithm for detection, called group positive RIVAL, that encourages the selection of groups of sub-spectra rather than the selection of individual sub-spectra that may be from the same parent isotope. Indeed, the proposed algorithm incorporates group positive LASSO, and, as such, we supply the consistency results of group positive LASSO and adaptive group positive LASSO. In an example employing various shielding materials and material thicknesses, group positive RIVAL is shown to perform well in all scenarios with the exception of ones in which the shielding material is lead. - Highlights: ► Identification of nuclides from weak and poorly resolved spectra. ► Shielding materials such as carbon, water, concrete, and lead are considered. ► Isotope spectra are decomposed into their sub-spectra. ► A variable selection algorithm is proposed that encourages group selection. ► Simulations demonstrate the proposed method's performance when nuclides have been shielded

  10. Shielding device for control rod in nuclear reactor

    International Nuclear Information System (INIS)

    Sakamaki, Kazuo; Tomatsu, Tsutomu.

    1995-01-01

    The device of the present invention shields radiation emitted from control rods to greatly reduce an operator's radiation exposure even if reactor water level is lowered and the upper portion of the control rod is exposed upon inspection of a BWR type reactor. Namely, a shield assembly has a structure comprising a set of four columnar shields in a two-row and two-column arrangement, which can be inserted into a control rod guide tube. Upon conducting inspection, the control rod is lowered into the control rod guide tube, and in this state, the columnar shields of the shield assembly are inserted to the control rod in the control rod guide tube. With such procedures, the upper portion of the control rod protruded from the control rod guide tube is covered with the shield assembly. As a result, radiation leaked from the control rod is shielded. Accordingly, irradiation in the reactor due to leaked radiation can be prevented thereby enabling to reduce an operator's radiation exposure. (I.S.)

  11. Shielding property of bismuth glass based on MCNP 5 and WINXCOM simulated calculation

    International Nuclear Information System (INIS)

    Zhang Zhicheng; Zhang Jinzhao; Liu Ze; Lu Chunhai; Chen Min

    2013-01-01

    Background: Currently, lead glass is widely used as observation window, while lead is toxic heavy metal. Purpose: Non-toxic materials and their shielding effects are researched in order to find a new material to replace lead containing material. Methods: The mass attenuation coefficients of bismuth silicate glass were investigated with gamma-ray's energy at 0.662 MeV, 1.17 MeV and 1.33 MeV, respectively, by MCNP 5 (Monte Carlo) and WINXCOM program, and compared with those of the lead glass. Results: With attenuation factor K, shielding and mechanical properties taken into consideration bismuth glass containing 50% bismuth oxide might be selected as the right material. Dose rate distributions of water phantom were calculated with 2-cm and 10-cm thick glass, respectively, irradiated by 137 Cs and 60 Co in turn. Conclusion: Results show that the bismuth glass may replace lead glass for radiation shielding with appropriate energy. (authors)

  12. Characterization by Monte Carlo of the dose after a glass shield lead for gamma ray; Caracterizacion por Monte Carlo de la dosis tras un blindaje de vidrio de plomo para rayos gamma

    Energy Technology Data Exchange (ETDEWEB)

    Esteve Sanchez, S.; Gil Conde, M.; Contreras Gonzalez, J. L.; Rosado, J.; Pazyi, V.

    2013-07-01

    When a gamma-ray beam crosses the border between two media characterized by atomic number very different is they produce effects on the distribution of doses near the border difficult to predict with simple models. The case of rays gamma affecting a lead glass is particularly interesting for its application to shielding of common use. interested in studying the importance of the residual dose after the shield. (Author)

  13. The manufacturing of depleted uranium biological shield components

    International Nuclear Information System (INIS)

    Metelkin, J.A.

    1998-01-01

    The unique combination of the physical and mechanical properties of uranium made it possible to manufacture biological shield components of transport package container (TPC) for transportation nuclear power plant irradiated fuel and radionuclides of radiation diagnostic instruments. Protective properties are substantially dependent on the nature radionuclide composition of uranium, that why I recommended depleted uranium after radiation chemical processing. Depleted uranium biological shield (DUBS) has improved specific mass-size characteristics compared to a shield made of lead, steel or tungsten. Technological achievements in uranium casting and machining made it possible to manufacture DUBS components of TPC up to 3 tons of mass and up to 2 metres of the maximum size. (authors)

  14. A history of radiation shielding of x-ray therapy rooms

    International Nuclear Information System (INIS)

    McGinley, P.H.; Miner, M.S.

    1996-01-01

    In this report the history of shielding for radiation treatment rooms is traced from the time of the discovery of x rays to the present. During the early part of the twentieth century the hazards from ionizing radiation were recognized and the use of lead and other materials became common place for shielding against x rays. Techniques for the calculation of the shield thickness needed for x ray protection were developed in the 1920's, and shielding materials were characterized in terms of the half value layer or simple exponential factors. At the same time, better knowledge of the interaction between radiation and matter was acquired. With the development of high energy medical accelerators after 1940, new and more complex shielding problems had to be addressed. Recently, shielding requirements have become more stringent as standards for exposure of personnel and the general public have been reduced. The art of shielding of radiation treatment facilities is still being developed, and the need for a revision of the reports on shielding of medical accelerators from the National Council on Radiation Protection and Measurements is emphasized in this article. (author). 61 Refs., 3 Tabs

  15. Comparison of deterministic and Monte Carlo methods in shielding design.

    Science.gov (United States)

    Oliveira, A D; Oliveira, C

    2005-01-01

    In shielding calculation, deterministic methods have some advantages and also some disadvantages relative to other kind of codes, such as Monte Carlo. The main advantage is the short computer time needed to find solutions while the disadvantages are related to the often-used build-up factor that is extrapolated from high to low energies or with unknown geometrical conditions, which can lead to significant errors in shielding results. The aim of this work is to investigate how good are some deterministic methods to calculating low-energy shielding, using attenuation coefficients and build-up factor corrections. Commercial software MicroShield 5.05 has been used as the deterministic code while MCNP has been used as the Monte Carlo code. Point and cylindrical sources with slab shield have been defined allowing comparison between the capability of both Monte Carlo and deterministic methods in a day-by-day shielding calculation using sensitivity analysis of significant parameters, such as energy and geometrical conditions.

  16. Comparison of deterministic and Monte Carlo methods in shielding design

    International Nuclear Information System (INIS)

    Oliveira, A. D.; Oliveira, C.

    2005-01-01

    In shielding calculation, deterministic methods have some advantages and also some disadvantages relative to other kind of codes, such as Monte Carlo. The main advantage is the short computer time needed to find solutions while the disadvantages are related to the often-used build-up factor that is extrapolated from high to low energies or with unknown geometrical conditions, which can lead to significant errors in shielding results. The aim of this work is to investigate how good are some deterministic methods to calculating low-energy shielding, using attenuation coefficients and build-up factor corrections. Commercial software MicroShield 5.05 has been used as the deterministic code while MCNP has been used as the Monte Carlo code. Point and cylindrical sources with slab shield have been defined allowing comparison between the capability of both Monte Carlo and deterministic methods in a day-by-day shielding calculation using sensitivity analysis of significant parameters, such as energy and geometrical conditions. (authors)

  17. Design of ITER shielding blanket

    International Nuclear Information System (INIS)

    Furuya, Kazuyuki; Sato, Satoshi; Hatano, Toshihisa; Tokami, Ikuhide; Kitamura, Kazunori; Miura, Hidenori; Ito, Yutaka; Kuroda, Toshimasa; Takatsu, Hideyuki

    1997-05-01

    A mechanical configuration of ITER integrated primary first wall/shield blanket module were developed focusing on the welded attachment of its support leg to the back plate. A 100 mm x 150 mm space between the legs of adjacent modules was incorporated for the working space of welding/cutting tools. A concept of coolant branch pipe connection to accommodate deformation due to the leg welding and differential displacement of the module and the manifold/back plate during operation was introduced. Two-dimensional FEM analyses showed that thermal stresses in Cu-alloy (first wall) and stainless steel (first wall coolant tube and shield block) satisfied the stress criteria following ASME code for ITER BPP operation. On the other hand, three-dimensional FEM analyses for overall in-vessel structures exhibited excessive primary stresses in the back plate and its support structure to the vacuum vessel under VDE disruption load and marginal stresses in the support leg of module No.4. Fabrication procedure of the integrated primary first wall/shield blanket module was developed based on single step solid HIP for the joining of Cu-alloy/Cu-alloy, Cu-alloy/stainless steel, and stainless steel/stainless steel. (author)

  18. Shielding wall for thermonuclear device

    International Nuclear Information System (INIS)

    Uchida, Takaho.

    1989-01-01

    This invention concerns shielding walls opposing to plasmas of a thermonuclear device and it is an object thereof to conduct reactor operation with no troubles even if a portion of shielding wall tiles should be damaged. That is, the shielding wall tiles are constituted as a dual layer structure in which the lower base tiles are connected by means of bolts to first walls. Further, the upper surface tiles are bolt-connected to the layer base tiles. In this structure, the plasma thermal loads are directly received by the surface layer tiles and heat is conducted by means of conduction and radiation to the underlying base tiles and the first walls. Even upon occurrence of destruction accidents to the surface layer tiles caused by incident heat or electromagnetic force upon elimination of plasmas, since the underlying base tiles remain as they are, the first walls constituted with stainless steels, etc. are not directly exposed to the plasmas. Accordingly, the integrity of the first walls having cooling channels can be maintained and sputtering intrusion of atoms of high atom number into the plasmas can be prevented. (I.S.)

  19. Dosimetric characteristics of Thermo-Shield material for orthovoltage photon beams

    International Nuclear Information System (INIS)

    Bahmaid, Mohammad; Kim, Siyong; Liu, Chihray R.; Palta, Jatinder R.

    2003-01-01

    Conventionally, lead has been used for field shaping in orthovoltage radiation therapy. Recently, a compensator material named Thermo-Shield was presented for field shaping in electron beams. Thermo-Shield is composed of nontoxic, high atomic weight metal particles dispersed in a thermoplastic matrix. It is manually moldable and conforms to human anatomy or any shape at temperatures of 108-132 degree sign F. It is reusable and can be continuously reshaped to better fit the treatment field. Dosimetric characteristics of thermoplastic material were studied for Philips RT250 orthovoltage photon beams ranging from 75 to 250 kVp. It was found that Thermo-Shield should be four to five times thicker than lead to achieve the same transmission (less than 5%). However, it did not cause significant degradation in penumbra. Clinical procedures for use are discussed

  20. Gamma rays shielding and sensing application of some rare earth doped lead-alumino-phosphate glasses

    Science.gov (United States)

    Kaur, Preet; Singh, Devinder; Singh, Tejbir

    2018-03-01

    Seven rare earth (Sm3+, Eu3+ and Nd3+) doped lead alumino phosphate glasses were prepared. The protective and sensing measures from gamma rays were analysed in terms of parameters viz. density (ρ), refractive index, energy band gap (Eg), mean free path (mfp), effective atomic number (Zeff) and buildup factors (energy absorption EABF as well as exposure buildup factor EBF). The energy dependent parameters (mfp, Zeff, EABF and EBF) were investigated in the energy region from 15 keV to 15 MeV. EABF and EBF values were observed to be maximum in the intermediate energy region. Besides, the EABF and EBF values for the prepared samples are shown to have strong dependence on chemical composition of the glass at lower energy, whereas, it is almost independent of chemical composition in higher energy region. The prepared glass samples are found to have potential applications in radiation shielding as well as radiation sensing, which further find numerous applications in the field of medicine and industry.

  1. Correlation of gamma ray shielding and structural properties of PbO–BaO–P{sub 2}O{sub 5} glass system

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Kulwinder; Singh, K.J., E-mail: kanwarjitsingh@yahoo.com; Anand, Vikas

    2015-04-15

    Highlights: • Transparent glass samples of the system 55PbO{sub x}BaO(45 − x)P{sub 2}O{sub 5} (x = 1 up to 5) have been prepared in the laboratory. • Gamma ray shielding properties improve with the addition of BaO. • Number of non-bridging oxygens decrease with the increase in the content of BaO. • Investigated glass system can be potential candidate as an alternate to conventional radiation shielding ‘concrete’. - Abstract: The presented work has been undertaken to evaluate the applicability of BaO doped PbO-P{sub 2}O{sub 5} glass system as gamma ray shielding material in terms of mass attenuation coefficient and half value layer at photon energies 662, 1173 and1332 keV. A meaningful comparison of their radiation shielding properties has been made in terms of their mass attenuation coefficient and HVL parameters with standard radiation shielding concrete ‘barite’. The density, molar volume, XRD, FTIR, Raman and UV–visible techniques and mechanical properties (by Yamane and Mackenzie's procedure) have been used to study the structural properties of the prepared glass system in order to check the possibility of their commercial utility as alternate to conventional concrete for gamma ray shielding applications.

  2. Comparison of radiation shielding requirements for HDR brachytherapy using 169Yb and 192Ir sources

    International Nuclear Information System (INIS)

    Lymperopoulou, G.; Papagiannis, P.; Sakelliou, L.; Georgiou, E.; Hourdakis, C. J.; Baltas, D.

    2006-01-01

    169 Yb has received a renewed focus lately as an alternative to 192 Ir sources for high dose rate (HDR) brachytherapy. Following the results of a recent work by our group which proved 169 Yb to be a good candidate for HDR prostate brachytherapy, this work seeks to quantify the radiation shielding requirements for 169 Yb HDR brachytherapy applications in comparison to the corresponding requirements for the current 192 Ir HDR brachytherapy standard. Monte Carlo simulation (MC) is used to obtain 169 Yb and 192 Ir broad beam transmission data through lead and concrete. Results are fitted to an analytical equation which can be used to readily calculate the barrier thickness required to achieve a given dose rate reduction. Shielding requirements for a HDR brachytherapy treatment room facility are presented as a function of distance, occupancy, dose limit, and facility workload, using analytical calculations for both 169 Yb and 192 Ir HDR sources. The barrier thickness required for 169 Yb is lower than that for 192 Ir by a factor of 4-5 for lead and 1.5-2 for concrete. Regarding 169 Yb HDR brachytherapy applications, the lead shielding requirements do not exceed 15 mm, even in highly conservative case scenarios. This allows for the construction of a lead door in most cases, thus avoiding the construction of a space consuming, specially designed maze. The effects of source structure, attenuation by the patient, and scatter conditions within an actual treatment room on the above-noted findings are also discussed using corresponding MC simulation results

  3. Electromagnetic shielding

    International Nuclear Information System (INIS)

    Tzeng, Wen-Shian V.

    1991-01-01

    Electromagnetic interference (EMI) shielding materials are well known in the art in forms such as gaskets, caulking compounds, adhesives, coatings and the like for a variety of EMI shielding purposes. In the past, where high shielding performance is necessary, EMI shielding has tended to use silver particles or silver coated copper particles dispersed in a resin binder. More recently, aluminum core silver coated particles have been used to reduce costs while maintaining good electrical and physical properties. (author). 8 figs

  4. An attenuation Layer for Electromagnetic Shielding in X- Band Frequency

    Directory of Open Access Journals (Sweden)

    Vida Zaroushani

    2015-06-01

    Full Text Available Uncontrolled exposure to X-band frequency leads to health damage. One of the principles of radiation protection is shielding. But, conventional shielding materials have disadvantages. Therefore, studies of novel materials, as an alternative to conventional shielding materials, are required to obtain new electromagnetic shielding material. Therefore, this study investigated the electromagnetic shielding of two component epoxy thermosetting resin for the X - band frequency with workplace approach. Two components of epoxy resin mixed according to manufacturing instruction with the weight ratio that was 100:10 .Epoxy plates fabricated in three different thicknesses (2, 4 and 6mm and shielding effectiveness measured by Vector Network Analyzer. Then, shielding effectiveness measured by the scattering parameters.The results showed that 6mm thickness of epoxy had the highest and 2mm had the lowest average of shielding effectiveness in X-band frequency that is 4.48 and 1.9 dB, respectively. Also, shielding effectiveness increased by increasing the thickness. But this increasing is useful up to 4mm. Percentage shielding effectiveness of attenuation for 6, 4 and 2mm thicknesses is 64.35%, 63.31% and 35.40%. Also, attenuation values for 4mm and 6mm thicknesses at 8.53 GHz and 8.52 GHz frequency are 77.15% and 82.95%, respectively, and can be used as favourite shields for the above frequency. 4mm-Epoxy is a suitable candidate for shielding application in X-band frequency range but, in the lower section, 6mm thickness is recommended. Finely, the shielding matrix can be used for selecting the proper thickness for electromagnetic shielding in X- Band frequency.

  5. Two-dimensional shielding benchmarks for iron at YAYOI, (1)

    International Nuclear Information System (INIS)

    Oka, Yoshiaki; An, Shigehiro; Kasai, Shigeru; Miyasaka, Shun-ichi; Koyama, Kinji.

    The aim of this work is to assess the collapsed neutron and gamma multigroup cross sections for two dimensional discrete ordinate transport code. Two dimensional distributions of neutron flux and gamma ray dose through a 70cm thick and 94cm square iron shield were measured at the fast neutron source reactor ''YAYOI''. The iron shield was placed over the lead reflector in the vertical experimental column surrounded by heavy concrete wall. The detectors used in this experiment were threshold detectors In, Ni, Al, Mg, Fe and Zn, sandwitch resonance detectors Au, W and Co, activation foils Au for neutrons and thermoluminescence detectors for gamma ray dose. The experimental results were compared with the calculated ones by the discrete ordinate transport code ANISN and TWOTRAN. The region-wise, coupled neutron-gamma multigroup cross-sections (100n+20gamma, EURLIB structure) were generated from ENDF/B-IV library for neutrons and POPOP4 library for gamma-ray production cross-sections by using the code system RADHEAT. The effective microscopic neutron cross sections were obtained from the infinite dilution values applying ABBN type self-shielding factors. The gamma ray production multigroup cross-sections were calculated from these effective microscopic neutron cross-sections. For two-dimensional calculations the group constants were collapsed into 10 neutron groups and 3 gamma groups by using ANISN. (auth.)

  6. [Trial manufacture of a plunger shield for a disposable plastic syringe].

    Science.gov (United States)

    Murakami, Shigeki; Emoto, Takashi; Mori, Hiroshige; Fujita, Katsuhisa; Kubo, Naoki

    2008-08-20

    A syringe-type radiopharmaceutical being supplied by a manufacturer has a syringe shield and a plunger shield, whereas an in-hospital labeling radiopharmaceutical is administered by a disposable plastic syringe without the plunger shield. In cooperation with Nihon Medi-Physics Co. Ltd., we have produced a new experimental plunger shield for the disposable plastic syringe. In order to evaluate this shielding effect, we compared the leaked radiation doses of our plunger shield with those of the syringe-type radiopharmaceutical (Medi shield type). Our plunger shield has a lead plate of 21 mm in diameter and 3 mm thick. This shield is equipped with the plunger-end of a disposal plastic syringe. We sealed 99mTc solution into a plastic syringe (Terumo Co.) of 5 ml with our plunger shield and Medi shield type of 2 ml. We measured leaked radiation doses around syringes using fluorescent glass dosimeters (Dose Ace). The number of measure points was 18. The measured doses were converted to 70 microm dose equivalent at 740 MBq of radioactivity. The results of our plunger shield and the Medi shield type were as follows: 4-13 microSv/h and 3-14 microSv/h at shielding areas, 3-545 microSv/h and 6-97 microSv/h at non-shielding areas, 42-116 microSv/h and 88-165 microSv/h in the vicinity of the syringe shield, and 1071 microSv/h and 1243 microSv/h at the front of the needle. For dose rates of shielding areas around the syringe, the shielding effects were approximately the same as those of the Medi shield type. In conclusion, our plunger shield may be useful for reducing finger exposure during the injection of an in-hospital labeled radiopharmaceutical.

  7. Poor Utility of Gonadal Shielding for Pediatric Pelvic Radiographs.

    Science.gov (United States)

    Lee, Mark C; Lloyd, Jessica; Solomito, Matthew J

    2017-07-01

    Plain pelvic radiographs are commonly used for a variety of pediatric orthopedic disorders. Lead shielding is typically placed over the gonads to minimize radiation exposure to these sensitive tissues. However, misplaced shielding can sabotage efforts to protect patients from excessive radiation exposure either by not covering radiosensitive tissues or by obscuring anatomic areas of interest, prompting repeat radiographic examinations. The goal of this study was to determine the incidence of misplaced shielding for pelvic radiographs obtained for pediatric orthopedic evaluation. Children 8 to 16 years old who had an anteroposterior or frog lateral pelvic radiograph between 2008 and 2014 were included. A total of 3400 patients met the inclusion criteria, and 84 boys and 84 girls were randomly selected for review. For both boys and girls, the percentage of incorrectly positioned or missing shields was calculated. Chi-square testing was used to compare the frequency of missing or incorrectly placed shields between sexes and age groups. Pelvic shields were misplaced in 49% of anteroposterior and 63% of frog lateral radiographs. Shielding was misplaced more frequently for girls than for boys on frog lateral radiographs (76% vs 51%; P<.05). Pelvic bony landmarks were often obscured by pelvic shielding, with a frequency of 7% to 43%, depending on the specific landmark. The femoral head and acetabulum were obscured by shielding in up to 2% of all images. The findings suggest that accepted pelvic shielding protocols are ineffective. Consideration should be given to alternative protocols or abandonment of this practice. [Orthopedics. 2017; 40(4):e623-e627.]. Copyright 2017, SLACK Incorporated.

  8. Synthesis of mullite (3Al2O32SiO2) from local kaolin for radiation shielding

    Science.gov (United States)

    Ripin, Azuhar; Mohamed, Faizal; Aman, Asyraf

    2018-04-01

    Raw kaolin from Kota Tinggi, Johor was used in this study to produce ceramic mullite (3Al2O22SiO2) for radiation shielding materials. In this work, an attempt was made to study the potential of local minerals to be used as a shielding barrier for diagnostic radiology radiation facilities in hospitals and medical centers throughout Malaysia. The conventional ceramic processing route was employed in the study using different pressing strength and sintering time. The obtained samples were characterized using X-ray diffractometer (XRD) for phase identification of each of the samples. The lead equivalent (LE) test was carried out using 15.05 mCi Cobalt-57 with gamma energy of 122 keV to compute the abilities of the mullite ceramic samples to attenuate the radiation. XRD patterns of prepared ceramics revealed the presence of orthorhombic mullite, hexagonal quartz and orthorhombic sillimanite structures. Furthermore, the radiation test displayed the ability of ceramics to shield of 70 % of gamma radiation at the distance of 60 cm from the radiation source. The highest lead equivalent thickness is 1.0 mm Pb and the lowest is about 0.06 mm Pb. From the result, it is shown that the ceramic has the potential to use as a shielding barrier in diagnostic radiology facilities due to the ability of reducing the radiation dose up to 70 % from its initial value.

  9. The construction of radiation shielding for baby ebm

    International Nuclear Information System (INIS)

    Mohd Rizal Md Chulan; Leo Kwee Wah; Lee Chee Huei; Muhamad Zahidee Taat; Fadzlie Nordin; Abu Bakar Mhd Ghazali; Mohd Yusof Ali; Mohd Rizal Mamat Ibrahim; Syed Nasaruddin Syed Idris; Mahmud Hamid; Mohd Khairi Mohd Said

    2005-01-01

    The construction of radiation shielding for electron beam machine, Baby EBM is necessary for prevention from x-ray (Bremstrahlung) that produced when electron bombarded the target material. The strength of produced x-ray is depending on electron energy and the atomic number of target material. In the construction process of radiation shielding, a few aspects need to be considered such as shielding material and its thickness to be used, mainframe for radiation shielding and the way fabrication to be done. In this project, the thickness of radiation shielding is calculated manually following the NCRP 51 guidelines whereas for frame design, shielding walls and fabrication is considered that the accelerator devices (accelerating tube, focusing device and neck) is vertically and the whole weight of Baby EBM. From the calculations, the thickness and the material for radiation shielding is to be used are 6mm lead. This radiation shielding has been tested (using the parameters that have been considered) to know the leak of radiation (at all surfaces) and direct radiation below 5 cm from the window. The value of high voltage that applied at accelerating tube is 80 kV and the voltage, current supply at electron gun is 3.0 V, 7.1 A respectively. The result of the testing found that dose rate under the window foil is more than 2000 mSv/hr and at all shielding surfaces are less than 0.5 mSv/hr, which is background reading and this is acceptable as compared to the theoretical calculation. The measurement was done using a survey meter typed Ludlum-model 3. (Author)

  10. About the Scythian Shields

    Directory of Open Access Journals (Sweden)

    About the Scythian Shields

    2017-10-01

    Full Text Available Shields played major role in the armament system of the Scythians. Made from organic materials, they are poorly traced on the materials of archaeological excavations. Besides, scaly surface of shields was often perceived in practice as the remnants of the scaly armor. E. V. Chernenko was able to discern the difference between shields’ scaly plates and armor scales. The top edge of the scales was bent inwards, and shield plates had a wire fixation. These observations let significantly increase the number of shields, found in the burial complexes of the Scythians. The comparison of archaeological materials and the images of Scythian warriors allow distinguishing the main forms of Scythian shields. All shields are divided into fencing shields and cover shields. The fencing shields include round wooden shields, reinforced with bronze sheet, and round moon-shaped shields with a notch at the top, with a metal scaly surface. They came to the Scythians under the Greek influence and are known in the monuments of the 4th century BC. Oval shields with scaly surface (back cover shields were used by the Scythian cavalry. They protected the rider in case of frontal attack, and moved back in case of maneuver or closein fighting. Scythian battle tactics were based on rapid approaching the enemy and throwing spears and further rapid withdrawal. Spears stuck in the shields of enemies, forcing them to drop the shields, uncover, and in this stage of the battle the archers attacked the disorganized ranks of the enemy. That was followed by the stage of close fight. Oval form of a wooden shield with leather covering was used by the Scythian infantry and spearmen. Rectangular shields, including wooden shields and the shields pleached from rods, represented a special category. The top of such shield was made of wood, and a pleached pad on leather basis was attached to it. This shield could be a reliable protection from arrows, but it could not protect against javelins

  11. Method for temporary shielding of reactor vessel internals

    International Nuclear Information System (INIS)

    Grimm, N.P.; Sejvar, J.

    1991-01-01

    This patent describes a method for shielding stored internals for reactor vessel annealing. It comprises removing nuclear fuel from the reactor vessel containment building; removing and storing upper and lower core internals under water in a refueling canal storage area; assembling a support structure in the refueling canal between the reactor vessel and the stored internals; introducing vertical shielding tanks individually through a hatch in the containment building and positioning each into the support structure; introducing horizontal shielding tanks individually through a hatch in the containment building and positioning each above the stored internals and vertical tanks; draining water from the refueling canal to the level of a flange of the reactor vessel; placing an annealing apparatus in the reactor vessel; pumping the remaining water from the reactor vessel; and annealing the reactor vessel

  12. Preliminary evaluation of FY98 KALIMER shielding design

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Jae Woon; Kang, Chang Mu; Kim, Young Jin [Korea Atomic Energy Research Institute, Taejon (Korea)

    1999-01-01

    This report describes a preliminary evaluation of the shielding design of FY98 KALIMER. The KALIMER shielding design includes the Inner Fixed Shield of a stainless cylinder located inside the support barrel; the Radial PSDRS Shields which are three B{sub 4}C cylinders located outside the support barrel at core level; the Lower IHX shield of a cylindrical B{sub 4}C plate located above the flow guide; and Inner and Outer IHX shields of B{sub 4}C cylinders located inside and outside of the support barrel, respectively. The DORT3.1 two-dimensional transport code was used to evaluate the KALIMER shielding design. The reactor system was represented by four axial zones, each of which was modeled in the R-Z geometry. The KAFAX-F22 library was used in the analyses, which was generated from the JEF-2.2 of OECD/NEA files for LMR applications by KAERI. The performance of the KALIMER shielding design is compared against the shielding design criteria. The results indicate that the support barrel, upper grid plate, and other reactor structures meet the maximum neutron fluence and DPA limits established in the shielding design criteria. Activities of the air effluent in the PSDRS were also evaluated and are shown to satisfy the maximum permissible concentration (MPC) limits in 10 CFR Part 20. In the future, the validation of the DORT model by a detailed three dimensional calculation such as MCNP and the justification of the current shielding design limits are needed. (author). 13 refs., 23 figs., 31 tabs.

  13. Radiation shielding performance of some concrete

    International Nuclear Information System (INIS)

    Akkurt, I.; Akyildirim, H.; Mavi, B.; Kilincarslan, S.; Basyigit, C.

    2007-01-01

    The energy consumption is increasing with the increased population of the world and thus new energy sources were discovered such as nuclear energy. Besides using nuclear energy, nuclear techniques are being used in a variety of fields such as medical hospital, industry, agriculture or military issue, the radiation protection becomes one of the important research fields. In radiation protection, the main rules are time, distance and shielding. The most effective radiation shields are materials which have a high density and high atomic number such as lead, tungsten which are expensive. Alternatively the concrete which produced using different aggregate can be used. The effectiveness of radiation shielding is frequently described in terms of the half value layer (HVL) or the tenth value layer (TVL). These are the thicknesses of an absorber that will reduce the radiation to half, and one tenth of its intensity respectively. In this study the radiation protection properties of different types of concrete will be discussed

  14. Survivor shielding. Part C. Improvements in terrain shielding

    International Nuclear Information System (INIS)

    Egbert, Stephen D.; Kaul, Dean C.; Roberts, James A.; Kerr, George D.

    2005-01-01

    A number of atomic-bomb survivors were affected by shielding provided by terrain features. These terrain features can be a small hill, affecting one or two houses, or a high mountain that shields large neighborhoods. In the survivor dosimetry system, terrain shielding can be described by a transmission factor (TF), which is the ratio between the dose with and without the terrain present. The terrain TF typically ranges between 0.1 and 1.0. After DS86 was implemented at RERF, the terrain shielding categories were examined and found to either have a bias or an excessive uncertainty that could readily be removed. In 1989, an improvement in the terrain model was implemented at RERF in the revised DS86 code, but the documentation was not published. It is now presented in this section. The solution to the terrain shielding in front of a house is described in this section. The problem of terrain shielding of survivors behind Hijiyama mountain at Hiroshima and Konpirasan mountain at Nagasaki has also been recognized, and a solution to this problem has been included in DS02. (author)

  15. Structural Shielding Design of a 6 MV Flattening Filter Free Linear Accelerator: Indian Scenario

    OpenAIRE

    Mishra, Bibekananda; Selvam, T. Palani; Sharma, P. K. Dash

    2017-01-01

    Detailed structural shielding of primary and secondary barriers for a 6 MV medical linear accelerator (LINAC) operated with flattening filter (FF) and flattening filter free (FFF) modes are calculated. The calculations have been carried out by two methods, one using the approach given in National Council on Radiation Protection (NCRP) Report No. 151 and the other based on the monitor units (MUs) delivered in clinical practice. Radiation survey of the installations was also carried out. NCRP a...

  16. A Survey of Structural Design of Diagnostic X-ray Imaging Facilities and Compliance to Shielding Design Goals in a Limited Resource Setting

    Directory of Open Access Journals (Sweden)

    Flavious B. Nkubli

    2017-11-01

    Full Text Available Purpose: To survey structural designs of x-ray rooms and compliance to shielding design goals of three x-ray imaging facilities. Methods and Materials: The survey was conducted in three radiodiagnostic centers in South East Nigeria, labeled X, Y and Z for anonymity. A stretchable non-elastic meter rule was used to measure x-ray room dimensions. A Vernier caliper was used to measure lead thickness while a calibrated digital survey meter Radalert 100x was used for radiation survey of controlled and uncontrolled areas. Simple statistical tools such as mean and standard deviation were used for analysis with the aid of Microsoft Excel version 2007. Results: Center X had a room dimension of 2.4 m × 2.1 m, Center Y had an x-ray room dimension of 3.6 m × 3.3 m, and Center Z had two x-ray rooms with identical dimensions of 6.3 m × 3.6 m. Measured exit radiation doses for controlled areas in all the centers were: 0.00152 mSv/wk; 0.00496 mSv/wk; 0.00168 mSv/wk; 0.00224 mSv/wk respectively. Lead was the common shielding material used. Conclusion: Based on the parameters studied, Center Z had the ideal room size and layout. Relative distances from the x-ray tubes to the nearest walls were not optimized in all the centers except in Center Z. Measured exit doses were within recommended limits except in Center Y. The location of the control consoles and measured doses were appropriate and within recommended design goals.

  17. Study on the Reinforcement Measures and Control Effect of the Surrounding Rock Stability Based on the Shield Tunneling Under Overpass Structure

    Directory of Open Access Journals (Sweden)

    Qian-cheng Fang

    2016-04-01

    Full Text Available To study the stability of surrounding rocks for shield tunneling under overpass structures and the safety of existing bridge structures, a practical example of the method was cited through a shield tunneling project under the overpass structure between K1+110 and K1+700 on Line 2 of Shenyang Subway, China. The sub-area reinforcement was proposed according to surrounding rock deformation characteristics during shield tunnel excavation. The bridge foundation (i.e., the clear spacing to the shield tunnel is less than 2 m was reinforced by steel support, the bridge foundation (the clear spacing is about 2~7m used “jet grouting pile” reinforcement, whereas the bridge foundation (the clear spacing is greater than 7 m did not adopt any reinforcement measures for the moment. For this study, the mean value and material heterogeneity models were established to evaluate the reinforcement effect from several aspects, such as surrounding rock deformation, plastic zone development, and safety factor. The simulation results were consistent with those of field monitoring. After reinforcement, the maximum deformation values of the surrounding rock were reduced by 4.9%, 12.2%, and 48.46%, and the maximum values of surface subsidence were decreased by 5.6%, 72.2%, and 88.64%. By contrast, the overall safety factor was increased by 4.1%, 55.46%, and 55.46%. This study posited that this reinforcement method can be adopted to solve tunnel construction problems in engineering-geological conditions effectively. References for evaluating similar projects are provided.

  18. Gamma-ray shielding design and performance test of WASTEF

    International Nuclear Information System (INIS)

    Matsumoto, Seiichiro; Aoyama, Saburo; Tashiro, Shingo; Nagai, Shiro

    1984-06-01

    The Waste Safety Testing Facility (WASTEF) was planned in 1978 to test the safety performance of HLW vitrified forms under the simulated conditions of long term storage and disposal, and completed in August 1981. The designed feature of the facility is to treat the vitrified forms contain actual high-level wastes of 5 x 10 4 Ci in maximum with 5 units of concrete shilded hot cells (3 units : Bate-Gamma cells, 2 units : Alpha-Gamma cells) and one units of Alpha-Gamma lead shielded cell, and to store radioactivity of 10 6 Ci in maximum. The safety performance of this facility is fundamentally maintained with confinement of radioactivity and shielding of the radiation. This report describes the method of gamma-ray shielding design, evaluation of the shielding test performed by using sealded gamma-ray sources(Co-60). (author)

  19. Conversion Factors for Predicting Unshielded Dose Rates in Shielded Waste

    International Nuclear Information System (INIS)

    Clapham, M.; Seamans Jr, J.V.; Arbon, R.E.

    2009-01-01

    This document describes the methodology developed and used by the Advanced Mixed Waste Treatment Project for determining the activity content and the unshielded surface dose rate for lead lined containers contaminated with transuranic waste. Several methods were investigated: - Direct measurement of the dose rate after removing the shielding. - Use of a MicroShield R derived dose conversion factor, (mRem/hr unshielded )/(mRem/hr shielded ), applied to the measured surface dose rate to estimate the unshielded surface dose rate. - Use of a MicroShield R derived activity conversion factor, mRem/hr unshielded /Ci, applied to the measured activity to estimate the unshielded dose rate. - Use of an empirically derived activity conversion factor, mRem/hr unshielded /Ci, applied to the measured activity to estimate the unshielded dose rate. The last approach proved to be the most efficacious by using a combination of nondestructive assay and empirically defined dose rate conversion factors. Empirically derived conversion factors were found to be highly dependent upon the matrix of the waste. Use of conversion factors relied on activity values corrected to address the presence of a lead liner. (authors)

  20. Studies of ionizing radiation shielding effectiveness of silica-based commercial glasses used in Bangladeshi dwellings

    Directory of Open Access Journals (Sweden)

    Sabina Yasmin

    2018-06-01

    Full Text Available Following the rapid growing economy, the Bangladeshi dwellers are replacing their traditional (mud-, bamboo-, and wood-based houses to modern multistoried buildings, where different types of glasses are being used as decorative as well as structural materials due to their various advantageous properties. In this study, we inquire the protective and dosimetric capability of commercial glasses for ionizing radiation. Four branded glass samples (PHP-Bangladesh, Osmania-Bangladesh, Nasir-Bangladesh, and Rider-China of same thickness and color but different elemental weight fractions were analyzed for shielding and dosimetric properties. The chemical composition of the studied material was evaluated by EDX technique. A well-shielded HPGe γ-ray spectrometer combined with associated electronics was used to evaluate the attenuation coefficients of the studied materials for 59 keV, 661 keV, 1173 keV and 1332 keV photon energies. A number of shielding parameters- half value layer (HVL, radiation protection efficiency (RPE and effective atomic number (Zeff were also evaluated. The data were compared with the available literature (where applicable to understand its shielding capability relative to the standard materials such as lead. Among the studied brands, Rider (China shows relatively better indices to be used as ionizing radiation shielding material. The obtained, Zeff of the studied glass samples showed comparable values to the TLD-200 dosimeter, thus considered suitable for environmental radiation monitoring purposes. Keywords: Silica-based commercial glass, HPGe γ-ray spectrometry, EDX analyses, Shielding effectiveness, Dosimetric properties

  1. Hydrogen Induced Cracking of Drip Shield

    Energy Technology Data Exchange (ETDEWEB)

    G. De

    2003-02-24

    One potential failure mechanism for titanium and its alloys under repository conditions is via the absorption of atomic hydrogen in the metal crystal lattice. The resulting decreased ductility and fracture toughness may lead to brittle mechanical fracture called hydrogen-induced cracking (HIC) or hydrogen embrittlement. For the current design of the engineered barrier without backfill, HIC may be a problem since the titanium drip shield can be galvanically coupled to rock bolts (or wire mesh), which may fall onto the drip shield, thereby creating conditions for hydrogen production by electrochemical reaction. The purpose of this scientific analysis and modeling activity is to evaluate whether the drip shield will fail by HIC or not under repository conditions within 10,000 years of emplacement. This Analysis and Model Report (AMR) addresses features, events, and processes related to hydrogen induced cracking of the drip shield. REV 00 of this AMR served as a feed to ''Waste Package Degradation Process Model Report'' and was developed in accordance with the activity section ''Hydrogen Induced Cracking of Drip Shield'' of the development plan entitled ''Analysis and Model Reports to Support Waste Package PMR'' (CRWMS M&O 1999a). This AMR, prepared according to ''Technical Work Plan for: Waste Package Materials Data Analyses and Modeling'' (BSC 2002), is to feed the License Application.

  2. Monte Carlo simulation of x-ray buildup factors of lead and its applications in shielding of diagnostic x-ray facilities

    International Nuclear Information System (INIS)

    Kharrati, Hedi; Agrebi, Amel; Karaoui, Mohamed-Karim

    2007-01-01

    X-ray buildup factors of lead in broad beam geometry for energies from 15 to 150 keV are determined using the general purpose Monte Carlo N-particle radiation transport computer code (MCNP4C). The obtained buildup factors data are fitted to a modified three parameter Archer et al. model for ease in calculating the broad beam transmission with computer at any tube potentials/filters combinations in diagnostic energies range. An example for their use to compute the broad beam transmission at 70, 100, 120, and 140 kVp is given. The calculated broad beam transmission is compared to data derived from literature, presenting good agreement. Therefore, the combination of the buildup factors data as determined and a mathematical model to generate x-ray spectra provide a computationally based solution to broad beam transmission for lead barriers in shielding x-ray facilities

  3. Onboard radiation shielding estimates for interplanetary manned missions

    International Nuclear Information System (INIS)

    Totemeier, A.; Jevremovic, T.; Hounshel, D.

    2004-01-01

    The main focus of space related shielding design is to protect operating systems, personnel and key structural components from outer space and onboard radiation. This paper summarizes the feasibility of a lightweight neutron radiation shield design for a nuclear powered, manned space vehicle. The Monte Carlo code MCNP5 is used to determine radiation transport characteristics of the different materials and find the optimized shield configuration. A phantom torso encased in air is used to determine a dose rate for a crew member on the ship. Calculation results indicate that onboard shield against neutron radiation coming from nuclear engine can be achieved with very little addition of weight to the space vehicle. The selection of materials and neutron transport analysis as presented in this paper are useful starting data to design shield against neutrons generated when high-energy particles from outer space interact with matter on the space vehicle. (authors)

  4. Shielding factors for gamma radiation from activity deposited on structures and ground surfaces

    International Nuclear Information System (INIS)

    Hedemann Jensen, P.

    1982-11-01

    This report describes a computer model that calculates shielding factors for indoor residence in multistorey and single-family houses for gamma radiation from activity despoited on roofs, outer walls, and ground surfaces. The dimensions of the buildings including window areas and the nearby surroundings has to be speficied in the calculations. Shielding factors can be calculated for different photon energies and for a uniform surface activity distribution as well as for separate activity on roof, outer wall, and ground surface achieved from decontamination or different deposition velocities. For a given area with a known distribution of different houses a weighted shielding factor can be calculated as well as a time-averaged one based on a given residence time distribution for work/school, home, outdoors, and transportation. Calculated shielding factors are shown for typical Danish houses. To give an impression of the sensitivity of the shielding factor on the parameters used in the model, variations were made in some of the most important parameters: wall thickness, road and ground width, percentage of outer wall covered by windows, photon energy, and decontamination percentage for outer walls, ground and roofs. The uncertainity of the calculations is discussed. (author)

  5. Shielding benchmark problems

    International Nuclear Information System (INIS)

    Tanaka, Shun-ichi; Sasamoto, Nobuo; Oka, Yoshiaki; Kawai, Masayoshi; Nakazawa, Masaharu.

    1978-09-01

    Shielding benchmark problems were prepared by the Working Group of Assessment of Shielding Experiments in the Research Comittee on Shielding Design of the Atomic Energy Society of Japan, and compiled by the Shielding Laboratory of Japan Atomic Energy Research Institute. Twenty-one kinds of shielding benchmark problems are presented for evaluating the calculational algorithm and the accuracy of computer codes based on the discrete ordinates method and the Monte Carlo method and for evaluating the nuclear data used in the codes. (author)

  6. Thyroid shields and neck exposures in cephalometric radiography

    Directory of Open Access Journals (Sweden)

    Cunha-Cruz Joana

    2006-06-01

    Full Text Available Abstract Background The thyroid is among the more radiosensitive organs in the body. The goal of this study was twofold: (1 to evaluate age-related changes in what is exposed to ionizing radiation in the neck area, and (2 to assess thyroid shield presence in cephalometric radiographs Methods Cephalometric radiographs at one academic setting were sampled and neck exposure was related to calendar year and patient's gender and age. Results In the absence of shields, children have more vertebrae exposed than adults (p Conclusion In the absence of a thyroid shield, children have more neck structure exposed to radiation than adults. In agreement with other reports, thyroid shield utilization in this study was low, particularly in children.

  7. Rifts of deeply eroded Hawaiian basaltic shields: A structural analog for large Martian volcanoes

    Science.gov (United States)

    Knight, Michael D.; Walker, G. P. L.; Mouginis-Mark, P. J.; Rowland, Scott K.

    1988-01-01

    Recently derived morphologic evidence suggests that intrusive events have not only influenced the growth of young shield volcanoes on Mars but also the distribution of volatiles surrounding these volcanoes: in addition to rift zones and flank eruptions on Arsia Mons and Pavonis Mons, melt water channels were identified to the northwest of Hecates Tholus, to the south of Hadriaca Patera, and to the SE of Olympus Mons. Melt water release could be the surface expression of tectonic deformation of the region or, potentially, intrusive events associated with dike emplacement from each of these volcanoes. In this study the structural properties of Hawaiian shield volcanoes were studied where subaerial erosion has removed a sufficient amount of the surface to enable a direct investigation of the internal structure of the volcanoes. The field investigation of dike morphology and magma flow characteristics for several volcanoes in Hawaii is reported. A comprehensive investigation was made of the Koolau dike complex that passes through the summit caldera. A study of two other dissected Hawaiian volcanoes, namely Waianae and East Molokai, was commenced. The goal is not only to understand the emplacement process and magma flow within these terrestrial dikes, but also to explore the possible role that intrusive events may have played in volcano growth and the distribution of melt water release on Mars.

  8. Rifts of deeply eroded Hawaiian basaltic shields: a structural analog for large Martian volcanoes

    International Nuclear Information System (INIS)

    Knight, M.D.; Walker, G.P.L.; Mouginis-Mark, P.J.; Rowland, S.K.

    1988-01-01

    Recently derived morphologic evidence suggests that intrusive events have not only influenced the growth of young shield volcanoes on Mars but also the distribution of volatiles surrounding these volcanoes: in addition to rift zones and flank eruptions on Arsia Mons and Pavonis Mons, melt water channels were identified to the northwest of Hecates Tholus, to the south of Hadriaca Patera, and to the SE of Olympus Mons. Melt water release could be the surface expression of tectonic deformation of the region or, potentially, intrusive events associated with dike emplacement from each of these volcanoes. In this study the structural properties of Hawaiian shield volcanoes were studied where subaerial erosion has removed a sufficient amount of the surface to enable a direct investigation of the internal structure of the volcanoes. The field investigation of dike morphology and magma flow characteristics for several volcanoes in Hawaii is reported. A comprehensive investigation was made of the Koolau dike complex that passes through the summit caldera. A study of two other dissected Hawaiian volcanoes, namely Waianae and East Molokai, was commenced. The goal is not only to understand the emplacement process and magma flow within these terrestrial dikes, but also to explore the possible role that intrusive events may have played in volcano growth and the distribution of melt water release on Mars

  9. Electromagnetic shielding effectiveness of 3D printed polymer composites

    Science.gov (United States)

    Viskadourakis, Z.; Vasilopoulos, K. C.; Economou, E. N.; Soukoulis, C. M.; Kenanakis, G.

    2017-12-01

    We report on preliminary results regarding the electromagnetic shielding effectiveness of various 3D printed polymeric composite structures. All studied samples were fabricated using 3D printing technology, following the fused deposition modeling approach, using commercially available filaments as starting materials. The electromagnetic shielding performance of the fabricated 3D samples was investigated in the so called C-band of the electromagnetic spectrum (3.5-7.0 GHz), which is typically used for long-distance radio telecommunications. We provide evidence that 3D printing technology can be effectively utilized to prepare operational shields, making them promising candidates for electromagnetic shielding applications for electronic devices.

  10. Shielding in electron beams used in radiotherapy

    International Nuclear Information System (INIS)

    Sentenac, Irenee.

    1979-01-01

    The interactions of electron beams with initial energies between 7 and 30 MeV have been studied in various materials including polystyrene, aluminium, copper and lead. The following experimental results have been found: estimation of measurement point displacement in a cylindrical chamber and of its variations with electron beam energy, empirical relations between the energy at the surface and the practical range of the electrons in various materials, an estimation of the relative ionisation due to the 'bremsstrahlung' measured behind different materials with beam complete shielding. Improvement of electron beam collimation is suggested after analysis of the dose distribution behind partial shielding [fr

  11. Shielding design study of the demonstration fast breeder reactor. 2. Shielding design on the basis of the JASPER analysis

    International Nuclear Information System (INIS)

    Suzuoki, Zenro; Tabayashi, Masao; Handa, Hiroyuki; Iida, Masaaki; Takemura, Morio

    2000-01-01

    Conceptual shielding design has been performed for the Demonstration Fast Breeder Reactor (DFBR) to achieve further optimization and reduction of the plant construction cost. The design took into account its implications in overall plant configuration such as reduction of shields in the core, adoption of fission gas plenum in the lower portion of fuel assemblies, and adoption of gas expansion modules. Shielding criteria applied for the design are to secure fast neutron fluence on in-vessel structures as well as responses of the nuclear instrumentation system and to restrict secondary sodium activation. The design utilized the cross sections and the one- and two-dimensional discrete ordinates transport codes, whose verification had been performed by the JASPER experiment analysis. Correction factors yielded by the JASPER analysis were applied to the design calculations to obtain design values with improved accuracy. Design margins, which are defined by the ratios of the design criteria to the design values, were more than two for all shielding issues of interest, showing the adequacy of the shielding design of the DFBR. (author)

  12. Where have the neutrons gone: A history of the Tower Shielding Facility

    International Nuclear Information System (INIS)

    Muckenthaler, F.J.

    1992-01-01

    In the early 1950's, the concept of the unit shield for the nuclear powered aircraft reactor changed to one of the divided shield concept where the reactor and crew compartment shared the shielding load. Design calculations for the divided shield were being made based on data obtained in studies for the, unit shield. It was believed that these divided shield designs were subject to error, the magnitude of which could not be estimated. This belief led to the design of the Tower Shielding Facility where divided-shield-type measurements could be made without interference from ground or structural scattering. This paper discusses that facility, its reactors, and some chosen experiments from the list of many that were performed at that facility during the past 38 years

  13. Studies of ionizing radiation shielding effectiveness of silica-based commercial glasses used in Bangladeshi dwellings

    Science.gov (United States)

    Yasmin, Sabina; Barua, Bijoy Sonker; Khandaker, Mayeen Uddin; Chowdhury, Faruque-Uz-Zaman; Rashid, Md. Abdur; Bradley, David A.; Olatunji, Michael Adekunle; Kamal, Masud

    2018-06-01

    Following the rapid growing economy, the Bangladeshi dwellers are replacing their traditional (mud-, bamboo-, and wood-based) houses to modern multistoried buildings, where different types of glasses are being used as decorative as well as structural materials due to their various advantageous properties. In this study, we inquire the protective and dosimetric capability of commercial glasses for ionizing radiation. Four branded glass samples (PHP-Bangladesh, Osmania-Bangladesh, Nasir-Bangladesh, and Rider-China) of same thickness and color but different elemental weight fractions were analyzed for shielding and dosimetric properties. The chemical composition of the studied material was evaluated by EDX technique. A well-shielded HPGe γ-ray spectrometer combined with associated electronics was used to evaluate the attenuation coefficients of the studied materials for 59 keV, 661 keV, 1173 keV and 1332 keV photon energies. A number of shielding parameters- half value layer (HVL), radiation protection efficiency (RPE) and effective atomic number (Zeff) were also evaluated. The data were compared with the available literature (where applicable) to understand its shielding capability relative to the standard materials such as lead. Among the studied brands, Rider (China) shows relatively better indices to be used as ionizing radiation shielding material. The obtained, Zeff of the studied glass samples showed comparable values to the TLD-200 dosimeter, thus considered suitable for environmental radiation monitoring purposes.

  14. Electromagnetic shielding formulae

    International Nuclear Information System (INIS)

    Dahlberg, E.

    1979-02-01

    This addendum to an earlier collection of electromagnetic shielding formulae (TRITA-EPP-75-27) contains simple transfer matrices suitable for calculating the quasistatic shielding efficiency for multiple transverse-field and axial-field cylindrical and spherical shields, as well as for estimating leakage fields from long coaxial cables and the normal-incidence transmission of a plane wave through a multiple plane shield. The differences and similarities between these cases are illustrated by means of equivalent circuits and transmission line analogies. The addendum also includes a discussion of a possible heuristic improvement of some shielding formulae. (author)

  15. Challenges in commercial manufacture of radiation shielding glasses

    International Nuclear Information System (INIS)

    Gupta, R.K.

    2011-01-01

    Radioactive hot-cells employ Radiation Shielding Windows (RSWs), assembled from specialty glasses, developed exclusively for nuclear industry. RSWs serve the twin purpose of direct viewing and shielding protection to the operator and use various types of radiation resistant and optically compatible glasses, such as low-density borosilicate glass; medium-density glass with up to 45% Lead and high-density glass with over 70% lead. Some glasses are Ceria-doped for enhancing their resistance threshold to radiation browning. A clear view of future requirement, capital and environmental costs could be the driving force towards bringing about changes in melting practices, encourage melting development, and enhancing collaboration. With DAE and CGCRI working in tandem, production of the entire range of RSW glasses by an Indian glass industry participant may no longer be a distant dream

  16. Gonad Shielding during Pelvic Radiography: A Systematic Review and Meta-analysis.

    Science.gov (United States)

    Karami, Vahid; Zabihzadeh, Mansour; Shams, Nasim; Saki Malehi, Amal

    2017-02-01

    Gonad shielding has been extensively advocated during pelvic radiography at or below reproductive ages. The popular practice of gonad shielding is placement of a lead shield in the midline of the pelvis. The aim of this study was to address the prevalence of gonad shielding and find out whether the current practice of gonad shielding can be considered as an effective method to reduce radiation exposure in patients undergoing pelvic radiography. National and international electronic databases, including PubMed, MEDLIN, EMBASE, and Google-Scholar, were searched up to January 2016. The database searches were supplemented with manual searches of reference lists. Two authors independently assessed the eligibility of all studies and extracted data. The searches yielded a total of 243 publications. After assessing each identified study against specific inclusion exclusion criteria, 18 studies were deemed as relevant for this review. The total prevalence rate of gonad shielding was estimated at 58% (95% CI: 40 to 74%). It was estimated that only 34% (95% CI: 25 to 44%) of the radiographs had correct positioning of the shield. Also, incorrect positioning of the shield was statistically significantly higher in females than males (85% vs. 52 %; P-value gonad shielding during female pelvic radiography should be no longer considered as an effective method to reduce radiation exposure. Training the best qualified radiographers is the key to accurate positioning of the shield in male subjects.

  17. Estimate of the shielding effect on secondary cancer risk due to cone-beam CT in image-guided radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Sung, Jiwon; Baek, Taeseong; Yoon, Myonggeun [Korea University, Seoul (Korea, Republic of); Kim, Dongwook; Kim, Donghyun [Kyung Hee University Hospital at Gangdong, Seoul (Korea, Republic of)

    2014-09-15

    This study evaluated the effect of a simple shielding method using a thin lead sheet on the imaging dose caused by cone-beam computed tomography (CBCT) in image-guided radiation therapy (IGRT). Reduction of secondary doses from CBCT was measured using a radio-photoluminescence glass dosimeter (RPLGD) placed inside an anthropomorphic phantom. The entire body, except for the region scanned by using CBCT, was shielded by wrapping it with a 2-mm lead sheet. Changes in secondary cancer risk due to shielding were calculated using BEIR VII models. Doses to out-of-field organs for head-and-neck, chest, and pelvis scans were decreased 15 ∼ 100%, 23 ∼ 90%, and 23 ∼ 98%, respectively, and the average reductions in lifetime secondary cancer risk due to the 2-mm lead shielding were 1.6, 11.5, and 12.7 persons per 100,000, respectively. These findings suggest that a simple, thin-lead-sheet-based shielding method can effectively decrease secondary doses to out-of-field regions for CBCT, which reduces the lifetime cancer risk on average by 9 per 100,000 patients.

  18. Concrete mix design for X-and gamma shielding

    International Nuclear Information System (INIS)

    Mohamad Pauzi Ismail; Noor Azreen Masenwat; Suhairy Sani; Abdul Bakhri Muhammad; Mohd Kamal Shah Shamsuddin; Rahmad Abd Rashid

    2012-01-01

    The design of X-ray or gamma ray radiographic exposure room requires some calculations on shielding to provide safe operation of the facility and minimum exposure to radiation workers. Careful design can lead to economical installations with minimal barriers. The design depends on such factors as: maximum energy, maximum intensity, permitted full-body dosage, workload, use factor, occupancy factor, maximum dose output and shielding materials. Choice of material for a barrier depends on convenience and cost. The radiographic exposure room is usually made of normal concrete with density of about 2.3 - 2.4 g/ cc. Normal concrete is often used for construction of exposure room because of cheap and ease of construction. This paper explained and discussed the optimum mix design for normal concrete used for X-and gamma shielding. (author)

  19. Space Shielding Materials for Prometheus Application

    Energy Technology Data Exchange (ETDEWEB)

    R. Lewis

    2006-01-20

    At the time of Prometheus program restructuring, shield material and design screening efforts had progressed to the point where a down-selection from approximately eighty-eight materials to a set of five ''primary'' materials was in process. The primary materials were beryllium (Be), boron carbide (B{sub 4}C), tungsten (W), lithium hydride (LiH), and water (H{sub 2}O). The primary materials were judged to be sufficient to design a Prometheus shield--excluding structural and insulating materials, that had not been studied in detail. The foremost preconceptual shield concepts included: (1) a Be/B{sub 4}C/W/LiH shield; (2) a Be/B{sub 4}C/W shield; (3) and a Be/B{sub 4}C/H{sub 2}O shield. Since the shield design and materials studies were still preliminary, alternative materials (e.g., {sup nal}B or {sup 10}B metal) were still being screened, but at a low level of effort. Two competing low mass neutron shielding materials are included in the primary materials due to significant materials uncertainties in both. For LiH, irradiation-induced swelling was the key issue, whereas for H{sub 2}O, containment corrosion without active chemistry control was key, Although detailed design studies are required to accurately estimate the mass of shields based on either hydrogenous material, both are expected to be similar in mass, and lower mass than virtually any alternative. Unlike Be, W, and B{sub 4}C, which are not expected to have restrictive temperature limits, shield temperature limits and design accommodations are likely to be needed for either LiH or H{sub 2}O. The NRPCT focused efforts on understanding swelting of LiH, and observed, from approximately fifty prior irradiation tests, that either casting ar thorough out-gassing should reduce swelling. A potential contributor to LiH swelling appears to be LiOH contamination due to exposure to humid air, that can be eliminated by careful processing. To better understand LiH irradiation performance and

  20. Study on box shield tunneling method in trial field operation; Box shield koho jissho seko ni kansuru kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Tada, K.; Taniguchi, T. [Toda Corp., Tokyo, (Japan); Furukawa, K.; Nakagawa, K. [Yamaguchi University, Yamaguchi (Japan). Faculty of Engineering

    1997-03-20

    This paper describes a rectangular section shield tunneling method as a part of developments of non-circular section shield tunneling methods. The non-circular shield is drawing attention because of need of excavation in small land available in urban areas and between congested existing structures, as well as reduction in the excavated soil amount. A full-scale machine was fabricated to perform a natural ground excavation experiment. The cutter units comprising two each of drum cutters and ring cutters were arranged above and below, by which two tunnels of 40 m long with a cross section of 2.85 m {times} 2.85 m were excavated. The natural ground was supported safely by holding mud water pressures at cutting points constant, thus stability of the cutting points was ensured. Back-filling has made complete filling of tail void (clearance between a segment and the ground) possible, resulting in suppression in conditional change of the surrounding ground. Attitude control has been performed properly as a result of correct selection of shield jacks and use of deflection jacks. Broken-type over-cutters were used to have constructed tunnels with curve radius of 80 and 100 m with high accuracy. Thrust and propulsion speed of the shield do not differ from those of circular shields. Possibilities of this construction method were verified. 8 refs., 26 figs., 2 tabs.

  1. Shielding in ungated field emitter arrays

    Energy Technology Data Exchange (ETDEWEB)

    Harris, J. R. [U.S. Navy Reserve, Navy Operational Support Center New Orleans, New Orleans, Louisiana 70143 (United States); Jensen, K. L. [Code 6854, Naval Research Laboratory, Washington, D.C. 20375 (United States); Shiffler, D. A. [Directed Energy Directorate, Air Force Research Laboratory, Albuquerque, New Mexico 87117 (United States); Petillo, J. J. [Leidos, Billerica, Massachusetts 01821 (United States)

    2015-05-18

    Cathodes consisting of arrays of high aspect ratio field emitters are of great interest as sources of electron beams for vacuum electronic devices. The desire for high currents and current densities drives the cathode designer towards a denser array, but for ungated emitters, denser arrays also lead to increased shielding, in which the field enhancement factor β of each emitter is reduced due to the presence of the other emitters in the array. To facilitate the study of these arrays, we have developed a method for modeling high aspect ratio emitters using tapered dipole line charges. This method can be used to investigate proximity effects from similar emitters an arbitrary distance away and is much less computationally demanding than competing simulation approaches. Here, we introduce this method and use it to study shielding as a function of array geometry. Emitters with aspect ratios of 10{sup 2}–10{sup 4} are modeled, and the shielding-induced reduction in β is considered as a function of tip-to-tip spacing for emitter pairs and for large arrays with triangular and square unit cells. Shielding is found to be negligible when the emitter spacing is greater than the emitter height for the two-emitter array, or about 2.5 times the emitter height in the large arrays, in agreement with previously published results. Because the onset of shielding occurs at virtually the same emitter spacing in the square and triangular arrays, the triangular array is preferred for its higher emitter density at a given emitter spacing. The primary contribution to shielding in large arrays is found to come from emitters within a distance of three times the unit cell spacing for both square and triangular arrays.

  2. Fusion Engineering Device (FED) first wall/shield design

    International Nuclear Information System (INIS)

    Sager, P.H.; Fuller, G.; Cramer, B.; Davisson, J.; Haines, J.; Kirchner, J.

    1981-01-01

    The torus of the Fusion Engineering Device (FED) is comprised of the bulk shield and its associated spool lstructure and support system, the first wall water-cooled panel and armor systems, and the pumped limiter. The bulk shielding is provided by ten shield sectors that are installed in the spool structure in such a way as to permit extraction of the sectors through the openings between adjacent toroidal field coils with a direct radial movement. The first wall armor is installed on the inboard and top interior walls of these sectors, and the water-cooled panels are installed on the outboard interior walls and the pumped limiter in the bottom of the sectors. The overall design of the first wall and shield system is described in this paper

  3. Effect of metal shielding on a wireless power transfer system

    Science.gov (United States)

    Li, Jiacheng; Huang, Xueliang; Chen, Chen; Tan, Linlin; Wang, Wei; Guo, Jinpeng

    2017-05-01

    In this paper, the effect of non-ferromagnetic metal shielding (NFMS) material on the resonator of wireless power transfer (WPT) is studied by modeling, simulation and experimental analysis. And, the effect of NFMS material on the power transfer efficiency (PTE) of WPT systems is investigated by circuit model. Meanwhile, the effect of ferromagnetic metal shielding material on the PTE of WPT systems is analyzed through simulation. A double layer metal shield structure is designed. Experimental results demonstrate that by applying the novel double layer metal shielding method, the system PTE increases significantly while the electromagnetic field of WPT systems declines dramatically.

  4. A polynomial–based function approach to point isotropic gamma-ray buildup factor data in double layered spherical shield of water and lead

    Directory of Open Access Journals (Sweden)

    M. H. Alamatsaz

    2014-03-01

    Full Text Available As the input of MCNP code (Monte Carlo N - Particle code system, a monoenergetic and isotropic point source with the energy rangeg from 0.3 to 10 MeV was placed at the center of a spherical material surrounded by another one. The first shielding material was water and the second one was lead. The total thickness of the shield varied between 2 to 10 mfp. Then, using the output of MCNCP, exposure build up factor was calculated. The MCNP computed data were analyzed by plotting the buildup factor as a function of each independent variable (energy, first material thickness and second material thickness and observing the trends. Based on the trends, we examined many different expressions with different number of constants. By MINUIT the FORTRAN program, the constants were calculated, which gave the best agreement between the MCNP-computed exposure buildup factors and those obtained by the formula. At last, we developed a polynomial formula with 11 constants that reproduced exposure buildup factor with a relative error below 2% (in comparison with the MCNP result.

  5. Oscillatory vapour shielding of liquid metal walls in nuclear fusion devices.

    Science.gov (United States)

    van Eden, G G; Kvon, V; van de Sanden, M C M; Morgan, T W

    2017-08-04

    Providing an efficacious plasma facing surface between the extreme plasma heat exhaust and the structural materials of nuclear fusion devices is a major challenge on the road to electricity production by fusion power plants. The performance of solid plasma facing surfaces may become critically reduced over time due to progressing damage accumulation. Liquid metals, however, are now gaining interest in solving the challenge of extreme heat flux hitting the reactor walls. A key advantage of liquid metals is the use of vapour shielding to reduce the plasma exhaust. Here we demonstrate that this phenomenon is oscillatory by nature. The dynamics of a Sn vapour cloud are investigated by exposing liquid Sn targets to H and He plasmas at heat fluxes greater than 5 MW m -2 . The observations indicate the presence of a dynamic equilibrium between the plasma and liquid target ruled by recombinatory processes in the plasma, leading to an approximately stable surface temperature.Vapour shielding is one of the interesting mechanisms for reducing the heat load to plasma facing components in fusion reactors. Here the authors report on the observation of a dynamic equilibrium between the plasma and the divertor liquid Sn surface leading to an overall stable surface temperature.

  6. Investigation on Shielding Failure of a Novel 400 kV Composite tower

    DEFF Research Database (Denmark)

    Wang, Qian; Jahangiri, Tohid; Bak, Claus Leth

    2018-01-01

    In this paper, the lightning shielding performance of a newly-designed 400 kV double-circuit composite tower is investigated. Based on a revised EGM method, traditional shielding failure regions, located at both sides of a traditional tower is no longer a big issue for the fully composite tower......, due to its unusual ‘Y’ configuration. Instead, a new unprotected region exists in the tower center. The maximum lightning current that can lead to shielding failure and the shielding failure rate (SFR) of the new tower are calculated. To verify results from the revised EGM method, a scale model test...... is conducted. Spatial shielding failure probability around the tower is calculated based on ratio of discharge paths recorded in the test. Moreover, based on test results, the maximum shielding failure lightning currents are obtained. Analysis and results derived from the revised EGM method and scale model...

  7. Calculation of a concrete shielding for an ILU-8 D electron accelerator

    International Nuclear Information System (INIS)

    Helal, A.; Imam, A.

    1996-01-01

    A concrete shielding for an electron accelerator of 1 MeV is suggested to replace its structural steel shielding. The thickness of such a shield is calculated. The calculational model used is based on standard and transmission curves given in the literature. The calculated concrete shielding is generally adequate to attenuate the accelerator produced radiation to a level 1 μ Gy/h or less at any point outside of the vault enclosure. 5 figs

  8. Calculation of a concrete shielding for an ILU-8 D electron accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Helal, A [Nuclear Research Center, AEA, Cairo (Egypt); Imam, A [National Center for Nuclear Safety and Radiation Control, AEA, Cairo (Egypt)

    1997-12-31

    A concrete shielding for an electron accelerator of 1 MeV is suggested to replace its structural steel shielding. The thickness of such a shield is calculated. The calculational model used is based on standard and transmission curves given in the literature. The calculated concrete shielding is generally adequate to attenuate the accelerator produced radiation to a level 1 {mu} Gy/h or less at any point outside of the vault enclosure. 5 figs.

  9. Method for calculating required shielding in medical x-ray rooms

    International Nuclear Information System (INIS)

    Karppinen, J.

    1997-10-01

    The new annual radiation dose limits - 20 mSv (previously 50 mSv) for radiation workers and 1 mSv (previously 5 mSv) for other persons - implies that the adequacy of existing radiation shielding must be re-evaluated. In principle, one could assume that the thicknesses of old radiation shields should be increased by about one or two half-value layers in order to comply with the new dose limits. However, the assumptions made in the earlier shielding calculations are highly conservative; the required shielding was often determined by applying the maximum high-voltage of the x-ray tube for the whole workload. A more realistic calculation shows that increased shielding is typically not necessary if more practical x-ray tube voltages are used in the evaluation. We have developed a PC-based calculation method for calculating the x-ray shielding which is more realistic than the highly conservative method formerly used. The method may be used to evaluate an existing shield for compliance with new regulations. As examples of these calculations, typical x-ray rooms are considered. The lead and concrete thickness requirements as a function of x-ray tube voltage and workload are also given in tables. (author)

  10. Gamma ray shielding and structural properties of PbO-P2O5-Na2WO4 glass system

    Science.gov (United States)

    Dogra, Mridula; Singh, K. J.; Kaur, Kulwinder; Anand, Vikas; Kaur, Parminder

    2017-05-01

    The present work has been undertaken to study the gamma ray shielding properties of PbO-P2O5-Na2WO4 glass system. The values of mass attenuation coefficient and half value layer parameter at photon energies 511, 662 and 1173 KeV have been determined using XCOM computer software developed by National Institute of Standards and Technology. The density, molar volume, XRD, UV-VIS and Raman studies have been performed to study the structural properties of the prepared glass system to check the possibility of the use of prepared samples as an alternate to conventional concrete for gamma ray shielding applications.

  11. Evaluation of the Prevalence and Utility of Gonad Shielding in Pediatrics Undergoing Pelvic X-Ray

    OpenAIRE

    Vahid Karami; Mansour Zabihzadeh; Nasim Shams; Saman Sarikhani

    2016-01-01

    Background: Gonad shielding has been recommended during pelvic x-rays since the 1950s. The popular method of gonad shielding is placement a lead shield in the midline of the pelvis. The aim of this study was to evaluate the prevalence and utility of gonad shielding in pediatrics undergoing pelvic x-rays.Materials and MethodsFollowing study approval, we retrospectively retrieved data from the digital image library of ten radiology depertments of Khuzestan provience-Iran to identify pediatric p...

  12. Design of the segment structure and coolant ducts for a fusion reactor blanket and shield

    International Nuclear Information System (INIS)

    Briaris, D.A.; Stanbridge, J.R.

    1978-05-01

    An outline design and analysis of a support structure for the replaceable first wall of a helium cooled fusion reactor blanket has been undertaken. The proposed structure supports all the segment gravitational loads with maximum deflections limited to < 10 mm, and is itself supported off the outer shield by a simple vee-in-groove arrangement. It is a feature of the design that the coaxial coolant pipes and the segment structure operate at the same temperature, making it possible for them to be integrated, thereby avoiding the necessity for pipe bellows. The requirements of cooling the inner arm of the structure and increasing the major radius of the torus by approximately = 0.5 m, have been identified as problems associated with the 'horseshoe' shaped structure applicable to the reactor with divertor. For a ring structure, i.e. reactor without divertor, these problems do not arise. (author)

  13. Incorrectly placed gonad shields: Effect on CT automatic exposure correction from four different scanners

    International Nuclear Information System (INIS)

    Martin Weber Kusk, R.T.

    2014-01-01

    Purpose: To examine the influence of incorrectly placed gonad shields on radiation dose when performing abdominal CT with automatic exposure correction, using systems from different vendors. Methods and materials: An anthropomorphic phantom was scanned without gonad shields, and with gonad shields placed in two different positions relative to the scan range. Dose Length Product was recorded. mA distribution in the longitudinal direction was plotted. Mean dose was compared using the t-test. Results: Three scanners showed different increase in relative DLP according to shield position. Conclusion: Care must be taken when placing lead shielding at CT and characteristics of each scanner should be known to the operator

  14. General Corrosion and Localized Corrosion of the Drip Shield

    Energy Technology Data Exchange (ETDEWEB)

    F. Hua

    2004-09-16

    The repository design includes a drip shield (BSC 2004 [DIRS 168489]) that provides protection for the waste package both as a barrier to seepage water contact and a physical barrier to potential rockfall. The purpose of the process-level models developed in this report is to model dry oxidation, general corrosion, and localized corrosion of the drip shield plate material, which is made of Ti Grade 7. This document is prepared according to ''Technical Work Plan For: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]). The models developed in this report are used by the waste package degradation analyses for TSPA-LA and serve as a basis to determine the performance of the drip shield. The drip shield may suffer from other forms of failure such as the hydrogen induced cracking (HIC) or stress corrosion cracking (SCC), or both. Stress corrosion cracking of the drip shield material is discussed in ''Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material'' (BSC 2004 [DIRS 169985]). Hydrogen induced cracking of the drip shield material is discussed in ''Hydrogen Induced Cracking of Drip Shield'' (BSC 2004 [DIRS 169847]).

  15. General Corrosion and Localized Corrosion of the Drip Shield

    International Nuclear Information System (INIS)

    F. Hua

    2004-01-01

    The repository design includes a drip shield (BSC 2004 [DIRS 168489]) that provides protection for the waste package both as a barrier to seepage water contact and a physical barrier to potential rockfall. The purpose of the process-level models developed in this report is to model dry oxidation, general corrosion, and localized corrosion of the drip shield plate material, which is made of Ti Grade 7. This document is prepared according to ''Technical Work Plan For: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]). The models developed in this report are used by the waste package degradation analyses for TSPA-LA and serve as a basis to determine the performance of the drip shield. The drip shield may suffer from other forms of failure such as the hydrogen induced cracking (HIC) or stress corrosion cracking (SCC), or both. Stress corrosion cracking of the drip shield material is discussed in ''Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material'' (BSC 2004 [DIRS 169985]). Hydrogen induced cracking of the drip shield material is discussed in ''Hydrogen Induced Cracking of Drip Shield'' (BSC 2004 [DIRS 169847])

  16. Effect of bedside shielding on air-kerma rates around gynecologic intracavitary brachytherapy patients containing 226Ra or 137Cs

    International Nuclear Information System (INIS)

    Papin, P.J.; Ramsey, M.J.; LaFontaine, R.L.; LePage, R.P.

    1990-01-01

    An anthropomorphic phantom was implanted with 226Ra or 137Cs gynecologic intracavitary brachytherapy sources. Air-kerma rate measurements were taken at 10-cm increments along a horizontal plane from the side of the bed at 50 cm, 87 cm, and 136 cm heights above the floor. Five portable lead shields were placed at the head, at the foot and along one side of the bed and readings were taken again at the corresponding heights above, below and behind the shields. The readings were normalized to 100-mg Ra equivalence, and air-kerma rate curves were drawn allowing for the comparison of 226Ra and 137Cs with and without lead shields. The data demonstrated that the air-kerma rates for 137Cs were reduced more than those for 226Ra with the use of the portable lead shields. There was four times the transmission with 226Ra than with 137Cs. The optimal placement was with the lateral bedside shields proximal to the head and foot closest to the bed, with the middle shield overlapping in back. The shields at the head and foot should extend out and overlap the bedside shields. The level of the sources should be positioned near the bottom of the shields. This information will provide the medical health physicist with an estimate of air-kerma rates for both 226Ra and 137Cs with and without shielding for evaluating personnel exposures as well as the effectiveness of current shielding in relation to radiation protection requirements in adjacent rooms or hallways

  17. Requirement for radiation shields of transportation pipe for on line inhalation gases from compact cyclotron in positron emission tomography

    International Nuclear Information System (INIS)

    Hachiya, Takenori; Hagami, Eiichi; Shoji, Yasuaki; Aizawa, Yasuo; Kanno, Iwao; Uemura, Kazuo; Handa, Masahiko; Mori, Junichi; Fukagawa, Akihisa.

    1989-01-01

    In the unit housing of a compact cyclotron and positron emission CT (PET), positron emitting gas such as 15 O, 11 C, C 15 O 2 , C 15 O etc. is supplied from a cyclotron to a PET room through a transportation pipe with an appropriate shield to reduce positron annihilation radiation. This paper discribes the effect of lead and concrete shields with various thickness. Using lead or concrete shield blocks with various thicknesses, radiation leakage through the shield was measured by an ionization chamber type survey meter during continuous and constant supply of 15 O gas of 1.85 GBq/min concentration which is the maximum dose for clinical use. The leakage radiation measured was 213.7, 56.0, 15.3, 5.0 μSv/week for lead shield with 1, 2, 3, and 4 cm thickness, respectively, and 193.3, 30.5 and 5.1 μSv/week for concrete shields with thickness of 10, 20, and 30 cm, respectively. The present study shows that to keep less than 300 μSv/week, which is the permissible dose rate of the boundary zone around the radiation controlled area by Japan Science and Technology Agency, it is required to use more than 8 mm thick lead shield or 7 cm thick concrete for continuous supply of 1.85 GBq/min 15 O gas. (author)

  18. Shielding of the patient's gonads during intramedullary interlocking femoral nailing.

    Science.gov (United States)

    Kwong, L M; Johanson, P H; Zinar, D M; Lenihan, M R; Herman, M W

    1990-12-01

    Levels of exposure to radiation were recorded at sixty sites in fifteen patients during intramedullary interlocking femoral nailing. Radiation film dosimeters were placed at four gonadal sites on each subject. A standard male-gonad cup or a pelvic drape of 0.5-millimeter-thick lead-equivalent was put in place to shield the gonads. A second set of four dosimeters was placed external to the shield to approximate unprotected exposure. The total duration of the fluoroscopy averaged five minutes (range, thirty seconds to fourteen minutes). The total exposure to radiation external to the shield was 35 +/- 34 millirems at the male gonadal sites and 17 +/- 11 millirems at the female gonadal sites. With use of the gonadal shield, exposure to radiation was not measurable in thirteen of the fifteen patients. The differences between the exposures of the shielded and unshielded sites to radiation were statistically significant (p less than 0.001). The highest level of gonadal exposure was found with the treatment of proximal femoral fractures and with the use of statically locked nails. Regardless of the conditions, and for all types of fractures and locations, our results demonstrated that gonadal shielding is justified.

  19. Shielding of the patient's gonads during intramedullary interlocking femoral nailing

    International Nuclear Information System (INIS)

    Kwong, L.M.; Johanson, P.H.; Zinar, D.M.; Lenihan, M.R.; Herman, M.W.

    1990-01-01

    Levels of exposure to radiation were recorded at sixty sites in fifteen patients during intramedullary interlocking femoral nailing. Radiation film dosimeters were placed at four gonadal sites on each subject. A standard male-gonad cup or a pelvic drape of 0.5-millimeter-thick lead-equivalent was put in place to shield the gonads. A second set of four dosimeters was placed external to the shield to approximate unprotected exposure. The total duration of the fluoroscopy averaged five minutes (range, thirty seconds to fourteen minutes). The total exposure to radiation external to the shield was 35 +/- 34 millirems at the male gonadal sites and 17 +/- 11 millirems at the female gonadal sites. With use of the gonadal shield, exposure to radiation was not measurable in thirteen of the fifteen patients. The differences between the exposures of the shielded and unshielded sites to radiation were statistically significant (p less than 0.001). The highest level of gonadal exposure was found with the treatment of proximal femoral fractures and with the use of statically locked nails. Regardless of the conditions, and for all types of fractures and locations, our results demonstrated that gonadal shielding is justified

  20. A contribution to shielding effectiveness analysis of shielded tents

    Directory of Open Access Journals (Sweden)

    Vranić Zoran M.

    2004-01-01

    Full Text Available An analysis of shielding effectiveness (SE of the shielded tents made of the metallised fabrics is given. First, two electromagnetic characteristic fundamental for coupling through electrically thin shield, the skin depth break frequency and the surface resistance or transfer impedance, is defined and analyzed. Then, the transfer function and the SE are analyzed regarding to the frequency range of interest to the Electromagnetic Compatibility (EMC Community.

  1. Structural considerations for the practical development of primary shielding of X-ray rooms of megavoltage

    International Nuclear Information System (INIS)

    Lava, Deise D.; Borges, Diogo da S.; Affonso, Renato R.W.; Moreira, Maria de L.; Guimaraes, Antonio C.F.

    2014-01-01

    Due to the necessity of the use of accelerators with voltages above 10 MV in medical facilities, becomes necessary to evaluate the efficiency of the thickness of shielding materials used in rooms that contain these devices. This work presents the development of an algorithm able to provide data in a practical way, regarding the thickness of materials that can be used for an effective shielding against primary beams from these equipment. The use of the computer language C ++ allowed developing a practical tool for determining the thickness of materials required to protect the public and Individuals Occupationally Exposed (IOEs) against major powers beams. Furthermore, it was considered by calculations Intensity Modulated Radiotherapy Technique (IMRT). The construction of this tool was based to ensure the dose limits established in the CNEN-NN-3.01. The dose limiting is done through the use of loops able to validate the efficiency of thickness determined by the algorithm itself, and ensure if the radiation dose exceeds the limits set by the standard, it will be the inclusion of sufficient Half-Reducer Layers in so that the dose is within the parameters established by the Brazilian National Nuclear Energy Commission (CNEN). The code validation is performed by comparing results obtained in the examples p recalculated in the NCRP Report-151 (Structural Shielding Design and Evaluation for megavoltage X and Gamma-Ray Radiotherapy Facilities) with the results generated by the code. The results are satisfactory and consistent with that report

  2. Calculated shielding factors for selected European houses

    International Nuclear Information System (INIS)

    Hedemann Jensen, P.

    1984-12-01

    Shielding factors for gamma radiation from activity deposited on structures and ground surfaces have been calculated with the computer model DEPSHIELD for single-family and multi-storey buildings in France, United Kingdom and Denmark. For all three countries it was found that the shielding factors for single-family houses are approximately a factor of 2 - 10 higher that those for buildings with five or more storeys. Away from doors and windows the shielding factors for French, British, and Danish single-family houses are in the range 0.03 - 0.1, 0.06 - 0.4, and 0.07 - 0.3, respectively. The uncertainties of the calculations are discussed and DEPSHIELD-results are compared with other methods as well as with experimental results. (author)

  3. Hypervelocity Impact Performance of Open Cell Foam Core Sandwich Panel Structures

    Science.gov (United States)

    Ryan, S.; Ordonez, E.; Christiansen, E. L.; Lear, D. M.

    2010-01-01

    Open cell metallic foam core sandwich panel structures are of interest for application in spacecraft micrometeoroid and orbital debris shields due to their novel form and advantageous structural and thermal performance. Repeated shocking as a result of secondary impacts upon individual foam ligaments during the penetration process acts to raise the thermal state of impacting projectiles ; resulting in fragmentation, melting, and vaporization at lower velocities than with traditional shielding configurations (e.g. Whipple shield). In order to characterize the protective capability of these structures, an extensive experimental campaign was performed by the Johnson Space Center Hypervelocity Impact Technology Facility, the results of which are reported in this paper. Although not capable of competing against the protection levels achievable with leading heavy shields in use on modern high-risk vehicles (i.e. International Space Station modules), metallic foam core sandwich panels are shown to provide a substantial improvement over comparable structural panels and traditional low weight shielding alternatives such as honeycomb sandwich panels and metallic Whipple shields. A ballistic limit equation, generalized in terms of panel geometry, is derived and presented in a form suitable for application in risk assessment codes.

  4. Theoretical and experimental determination of mass attenuation coefficients of lead-based ceramics and their comparison with simulation

    Directory of Open Access Journals (Sweden)

    Vejdani-Noghreiyan Alireza

    2016-01-01

    Full Text Available Mass attenuation coefficient of lead-based ceramics have been measured by experimental methods and compared with theoretical and Monte Carlo simulation results. Lead-based ceramics were prepared using mixed oxide method and the X-ray diffraction analysis was done to evaluate the crystal structure of the produced handmade ceramics. The experimental results show good agreement with theoretical and simulation results. However at two gamma ray energies, small differences between experimental and theoretical results have been observed. By adding other additives to ceramics and observing the changes in the shielding properties such as flexibility, one can synthesize and optimize ceramics as a neutron shield.

  5. Transparent fast neutron shielding material and shielding method

    International Nuclear Information System (INIS)

    Nashimoto, Tetsuji; Katase, Haruhisa.

    1993-01-01

    Polyisobutylene having a viscosity average molecular weight of 20,000 to 80,000 and a hydrogen atom density of greater than 7.0 x 10 22 /cm 3 is used as a fast neutron shielding material. The shielding material is excellent in the shielding performance against fast neutrons, and there is no worry of leakage even when holes should be formed to a vessel. Further, it is excellent in fabricability, relatively safe even upon occurrence of fire and, in addition, it is transparent to enable to observe contents easily. (T.M.)

  6. Assessment of the structural shielding integrity of some selected computed tomography facilities in the Greater Accra Region of Ghana

    International Nuclear Information System (INIS)

    Nkansah, A.

    2010-01-01

    The structural shielding integrity was assessed for four of the CT facilities at Trust Hospital, Korle-Bu Teaching Hospital, the 37 Military Hospital and Medical Imaging Ghana Ltd. in the Greater Accra Region of Ghana. From the shielding calculations, the concrete wall thickness computed are 120, 145, 140 and 155mm, for Medical Imaging Ghana Ltd. 37 Military, Trust Hospital and Korle-Bu Teaching Hospital respectively using Default DLP values. The wall thickness using Derived DLP values are 110, 110, 120 and 168mm for Medical Imaging Ghana Ltd, 37 Military Hospital, Trust Hospital and Korle-Bu Teaching Hospital respectively. These values are within the accepted standard concrete thickness of 102- 152mm prescribed by the National Council of Radiological Protection and measurement. The ultrasonic pulse testing indicated that all the sandcrete walls are of good quality and free of voids since pulse velocities estimated were approximately equal to 3.45km/s. an average dose rate measurement for supervised areas is 3.4 μSv/wk and controlled areas is 18.0 μSv/wk. These dose rates were below the acceptable levels of 100 μSv per week for the occupationally exposed and 20 μSv per week for members of the public provided by the ICRU. The results mean that the structural shielding thickness are adequate to protect members of the public and occupationally exposed workers (au).

  7. A 2D semi-analytical model for Faraday shield in ICP source

    International Nuclear Information System (INIS)

    Zhang, L.G.; Chen, D.Z.; Li, D.; Liu, K.F.; Li, X.F.; Pan, R.M.; Fan, M.W.

    2016-01-01

    Highlights: • In this paper, a 2D model of ICP with faraday shield is proposed considering the complex structure of the Faraday shield. • Analytical solution is found to evaluate the electromagnetic field in the ICP source with Faraday shield. • The collision-free motion of electrons in the source is investigated and the results show that the electrons will oscillate along the radial direction, which brings insight into how the RF power couple to the plasma. - Abstract: Faraday shield is a thin copper structure with a large number of slits which is usually used in inductive coupled plasma (ICP) sources. RF power is coupled into the plasma through these slits, therefore Faraday shield plays an important role in ICP discharge. However, due to the complex structure of the Faraday shield, the resulted electromagnetic field is quite hard to evaluate. In this paper, a 2D model is proposed on the assumption that the Faraday shield is sufficiently long and the RF coil is uniformly distributed, and the copper is considered as ideal conductor. Under these conditions, the magnetic field inside the source is uniform with only the axial component, while the electric field can be decomposed into a vortex field generated by changing magnetic field together with a gradient field generated by electric charge accumulated on the Faraday shield surface, which can be easily found by solving Laplace's equation. The motion of the electrons in the electromagnetic field is investigated and the results show that the electrons will oscillate along the radial direction when taking no account of collision. This interesting result brings insight into how the RF power couples into the plasma.

  8. Radiation shielding concrete

    International Nuclear Information System (INIS)

    Kunishima, Shigeru.

    1990-01-01

    The radiation shielding concretes comprise water, cement, fine aggregates consisting of serpentines and blown mist slags, coarse aggregates consisting of serpentines and kneading materials. Since serpentines containing a relatively great amount of water of crystallization in rocks as coarse aggregates and fine aggregates, the hydrogen content in the radiation shielding concretes is increased and the neutron shielding effect is improved. In addition, since serpentines are added as the fine aggregates and blown mists slags of a great specific gravity are used, the specific gravity of the shielding concretes is increased to improve the γ-ray shielding effect. Further, by the use of the kneading material having a water reducing effect and fluidizing effect, and by the bearing effect of the spherical blown mist slags used as the fine aggregates, concrete fluidity can be increased. Accordingly, workability of the radiation shielding concretes can be improved. (T.M.)

  9. Hot-cell shielding system for high power transmission in DUPIC fuel fabrication

    International Nuclear Information System (INIS)

    Kim, K.; Lee, J.; Park, J.; Yang, M.; Park, H.

    2000-01-01

    This paper presents a newly designed hot-cell shielding system for use in the development of DUPIC (Direct Use of spent PWR fuel In CANDU reactors) fuel at KAERI (Korea Atomic Energy Research Institute). This hot-cell shielding system that was designed to transmit high power to sintering furnace in-cell from the out-of-cell through a thick cell wall has three subsystems - a steel shield plug with embedded spiral cooling line, stepped copper bus bars, and a shielding lead block. The dose-equivalent rates of the hot-cell shielding system and of the apertures between this system and the hot-cell wall were calculated. Calculated results were compared with the allowable dose limit of the existing hot-cell. Experiments for examining the temperature changes of the shielding system developed during normal furnace operation were also carried out. Finally, gamma-ray radiation survey experiments were conducted by Co-60 source. It is demonstrated that, from both calculated and experimental results, the newly designed hot-cell shielding system meets all the shielding requirements of the existing hot-cell facility, enabling high power transmission to the in-cell sintering furnace. (author)

  10. A Shielding Analysis of Hot Cell for a 10 MW Research Reactor

    International Nuclear Information System (INIS)

    Alnajjar, Alaaddin; Park, Chang Je; Roh, Gyuhong; Lee, Byunchul

    2013-01-01

    In this paper, a shielding analysis has been performed for the hot cell in a 10 MW research reactor. Two kinds of shielding analysis code systems are used such as MCNPX2.7 and M-Shield7. The first one is Monte Carlo stochastic code and the second one is a deterministic point kernel code. The results are compared in this study. In order to obtain source term, the ORIGEN-S code is used for different kinds of source. Four kinds of sources are taken into consideration. From the simulation, it is also proposed that the proper thickness of shielding material and the maximum source capacity in the hot cell. This study shows preliminary analysis results of hot cell shielding for 10MW research reactor. Total four different source terms are considered such as spent fuel assembly, Ir-192, Mo-99, and I-131. For shielding material, general concrete, heavy concrete, and lead are used. MCNPX code is mainly used for a simplified hot cell model and the result are nearly consistent when compared with M-Shield code. Required shielding thickness and the hot cell capacity are also obtained for various criterion of surface dose rates

  11. Shielding augmentation of roll-on shield from NAPS to Kaiga-2

    International Nuclear Information System (INIS)

    Pradhan, A.S.; Kumar, A.N.

    2000-01-01

    Extensive radiation field surveys were conducted in NAPS and KAPS reactor buildings as a part of commissioning checks on radiation shielding. During such surveys, dose rate higher than the expected values were noticed in fuelling machine service areas. A movable shield, separating high field area fuelling machine vault and low field area fuelling machine service area, known as roll-on shield was identified as one of the causes of high field in fuelling machine service area along with weaker end-shield. This paper discusses systematic approach adopted in bringing down the dose rates in fuelling machine service area by augmentation of roll-on shield. (author)

  12. Effect of metal shielding on a wireless power transfer system

    Directory of Open Access Journals (Sweden)

    Jiacheng Li

    2017-05-01

    Full Text Available In this paper, the effect of non-ferromagnetic metal shielding (NFMS material on the resonator of wireless power transfer (WPT is studied by modeling, simulation and experimental analysis. And, the effect of NFMS material on the power transfer efficiency (PTE of WPT systems is investigated by circuit model. Meanwhile, the effect of ferromagnetic metal shielding material on the PTE of WPT systems is analyzed through simulation. A double layer metal shield structure is designed. Experimental results demonstrate that by applying the novel double layer metal shielding method, the system PTE increases significantly while the electromagnetic field of WPT systems declines dramatically.

  13. Structural design of shield-integrated thin-wall vacuum vessel and manufacturing qualification tests for International Thermonuclear Experimental Reactor (ITER)

    International Nuclear Information System (INIS)

    Shimizu, Katsusuke; Shibui, Masanao; Koizumi, Koichi; Kanamori, Naokazu; Nishio, Satoshi; Sasaki, Takashi; Tada, Eisuke

    1992-09-01

    Conceptual design of shield-integrated thin-wall vacuum vessel has been done for ITER (International Thermonuclear Experimental Reactor). The vacuum vessel concept is based on a thin-double-wall structure, which consists of inner and outer plates and rib stiffeners. Internal shielding structures, which provide neutron irradiation shielding to protect TF coils, are set up between the inner plate and the outer plate of the vessel to avoid complexity of machine systems such as supporting systems of blanket modules. The vacuum vessel is assembled/disassembled by remote handling, so that welding joints are chosen as on-site joint method from reliability of mechanical strength. From a view point of assembling TF coils, the vacuum vessel is separated at the side of port, and is divided into 32 segments similar to the ITER-CDA reference design. Separatrix sweeping coils are located in the vacuum vessel to reduce heat fluxes onto divertor plates. Here, the coil structure and attachment to the vacuum vessel have been investigated. A sectorized saddle-loop coil is available for assembling and disassembling the coil. To support electromagnetic loads on the coils, they are attached to the groove in the vacuum vessel by welding. Flexible multi-plate supporting structure (compression-type gravity support), which was designed during CDA, is optimized by investigating buckling and frequency response properties, and concept on manufacturing and fabrication of the gravity support are proposed. Partial model of the vacuum vessel is manufactured for trial, so that fundamental data on welding and fabrication are obtained. From mechanical property tests of weldment and partial models, mechanical intensity and behaviors of the weldment are obtained. Informations on FEM-modeling are obtained by comparing analysis results with experimental results. (author)

  14. Computer code for shielding calculations of x-rays rooms

    International Nuclear Information System (INIS)

    Affonso, R.R.W.; Borges, D. da S.; Lava, D.D.; Moreira, M. de L.; Guimarães, A.C.F.

    2015-01-01

    The building an effective barrier against ionizing radiation present in radiographic rooms requires consideration of many variables. The methodology used for thickness specification of primary and secondary, barrier of a traditional radiographic room, considers the following factors: Use Factor, Occupational Factor, distance between the source and the wall, Workload, Kerma in the air and distance between the patient and the source. With these data it was possible to develop a computer code, which aims to identify and use variables in functions obtained through graphics regressions provided by NCRP-147 (Structural Shielding Design for Medical X-Ray Imaging Facilities) report, for shielding calculation of room walls, and the walls of the dark room and adjacent areas. With the implemented methodology, it was made a code validation by comparison of results with a study case provided by the report. The obtained values for thickness comprise different materials such as concrete, lead and glass. After validation it was made a case study of an arbitrary radiographic room.The development of the code resulted in a user-friendly tool for planning radiographic rooms to comply with the limits established by CNEN-NN-3:01 published in september/2011. (authors)

  15. Wake Shield Target Protection

    International Nuclear Information System (INIS)

    Valmianski, Emanuil I.; Petzoldt, Ronald W.; Alexander, Neil B.

    2003-01-01

    The heat flux from both gas convection and chamber radiation on a direct drive target must be limited to avoid target damage from excessive D-T temperature increase. One of the possibilities of protecting the target is a wake shield flying in front of the target. A shield will also reduce drag force on the target, thereby facilitating target tracking and position prediction. A Direct Simulation Monte Carlo (DSMC) code was used to calculate convection heat loads as boundary conditions input into ANSYS thermal calculations. These were used for studying the quality of target protection depending on various shapes of shields, target-shield distance, and protective properties of the shield moving relative to the target. The results show that the shield can reduce the convective heat flux by a factor of 2 to 5 depending on pressure, temperature, and velocity. The protective effect of a shield moving relative to the target is greater than the protective properties of a fixed shield. However, the protective effect of a shield moving under the drag force is not sufficient for bringing the heat load on the target down to the necessary limit. Some other ways of diminishing heat flux using a protective shield are discussed

  16. Dosimetric evaluation of indigenously developed non-lead bilayered radiation protective aprons

    International Nuclear Information System (INIS)

    Senthilkumar, S.

    2018-01-01

    Radiation shielding garments are commonly used to protect medical patients and radiation workers from X-radiation exposure during diagnostic imaging in hospitals. Originally, protective aprons consisted of lead-impregnated vinyl with a shielding equivalent given in millimeters of lead. All contained up to 2 mm of lead. While lead has long been used to shield patients from X-rays, its toxicity poses a health threat if the protective apron containing the metal wear out or the lead gets damaged. However, lead garments must be treated as hazardous waste for disposal and are heavy, causing back strain and other orthopedic problems for those who must wear them for long periods of time. The main purpose of this work was to indigenously develop light weight non lead based bilayered radiation protective aprons and evaluate dosimetrically with different combination of fabricated non lead materials and commercially available lead based aprons

  17. ANALISIS KESELAMATAN TERMOHIDROLIK BULK SHIELDING REAKTOR KARTINI

    Directory of Open Access Journals (Sweden)

    Azizul Khakim

    2015-10-01

    Full Text Available ABSTRAK ANALISIS KESELAMATAN TERMOHIDROLIK BULK SHIELDING REAKTOR KARTINI. Bulk shielding merupakan fasilitas yang terintegrasi dengan reaktor Kartini yang berfungsi sebagai penyimpanan sementara bahan bakar bekas. Fasilitas ini merupakan fasilitas yang termasuk dalam struktur, sistem dan komponen (SSK yang penting bagi keselamatan. Salah satu fungsi keselamatan dari sistem penanganan dan penyimpanan bahan bakar adalah mencegah kecelakaan kekritisan yang tak terkendali dan membatasi naiknya temperatur bahan bakar. Analisis keselamatan paling kurang harus mencakup analisis keselamatan dari sisi neutronik dan termo hidrolik Bulk shielding. Analisis termo hidrolik ditujukan untuk memastikan perpindahan panas dan proses pendinginan bahan bakar bekas berjalan baik dan tidak terjadi akumulasi panas yang mengancam integritas bahan bakar. Code tervalidasi PARET/ANL digunakan untuk analisis pendinginan dengan mode konveksi alam. Hasil perhitungan menunjukkan bahwa mode pendinginan konvekasi alam cukup memadai dalam mendinginkan panas sisa tanpa mengakibatkan kenaikan temperatur bahan bakar yang signifikan. Kata kunci: Bulk shielding, bahan bakar bekas, konveksi alam, PARET.   ABSTRACT THERMAL HYDRAULIC SAFETY ANALYSIS OF BULK SHIELDING KARTINI REACTOR. Bulk shielding is an integrated facility to Kartini reactor which is used for temporary spent fuels storage. The facility is one of the structures, systems and components (SSCs important to safety. Among the safety functions of fuel handling and storage are to prevent any uncontrolable criticality accidents and to limit the fuel temperature increase. Safety analyses should, at least, cover neutronic and thermal hydraulic calculations of the bulk shielding. Thermal hydraulic analyses were intended to ensure that heat removal and the process of the spent fuels cooling takes place adequately and no heat accumulation that challenges the fuel integrity. Validated code, PARET/ANL was used for analysing the

  18. Optimum structure of Whipple shield against hypervelocity impact

    International Nuclear Information System (INIS)

    Lee, M

    2014-01-01

    Hypervelocity impact of a spherical aluminum projectile onto two spaced aluminum plates (Whipple shield) was simulated to estimate an optimum structure. The Smooth Particle Hydrodynamics (SPH) code which has a unique migration scheme from a rectangular coordinate to an axisymmetic coordinate was used. The ratio of the front plate thickness to sphere diameter varied from 0.06 to 0.48. The impact velocities considered here were 6.7 km/s. This is the procedure we explored. To guarantee the early stage simulation, the shapes of debris clouds were first compared with the previous experimental pictures, indicating a good agreement. Next, the debris cloud expansion angle was predicted and it shows a maximum value of 23 degree for thickness ratio of front bumper to sphere diameter of 0.23. A critical sphere diameter causing failure of rear wall was also examined while keeping the total thickness of two plates constant. There exists an optimum thickness ratio of front bumper to rear wall, which is identified as a function of the size combination of the impacting body, front and rear plates. The debris cloud expansion-correlated-optimum thickness ratio study provides a good insight on the hypervelocity impact onto spaced target system.

  19. Optimum structure of Whipple shield against hypervelocity impact

    Science.gov (United States)

    Lee, M.

    2014-05-01

    Hypervelocity impact of a spherical aluminum projectile onto two spaced aluminum plates (Whipple shield) was simulated to estimate an optimum structure. The Smooth Particle Hydrodynamics (SPH) code which has a unique migration scheme from a rectangular coordinate to an axisymmetic coordinate was used. The ratio of the front plate thickness to sphere diameter varied from 0.06 to 0.48. The impact velocities considered here were 6.7 km/s. This is the procedure we explored. To guarantee the early stage simulation, the shapes of debris clouds were first compared with the previous experimental pictures, indicating a good agreement. Next, the debris cloud expansion angle was predicted and it shows a maximum value of 23 degree for thickness ratio of front bumper to sphere diameter of 0.23. A critical sphere diameter causing failure of rear wall was also examined while keeping the total thickness of two plates constant. There exists an optimum thickness ratio of front bumper to rear wall, which is identified as a function of the size combination of the impacting body, front and rear plates. The debris cloud expansion-correlated-optimum thickness ratio study provides a good insight on the hypervelocity impact onto spaced target system.

  20. Neoproterozoic Structural Evolution of the NE-trending 620-540 Ma Ad-Damm Shear Zone, Arabian Shield, Saudi Arabia

    Science.gov (United States)

    Hamimi, Z.; El-Sawy, E. K.; El-Fakharan, A. S.; Shujoon, A.; Matsah, M.; El-Shafei, M.

    2012-04-01

    Ad-Damm Shear Zone (ASZ) is a NE-trending fault zone separating Jeddah and Asir tectonostratigraphic terranes in the Neoproterozoic juvenile Arabian Shield. ASZ extends ~380 km, with an average width ~2-3 km, from the eye-catching Ruwah Fault Zone in the eastern shield to the Red Sea Coastal plain. It was believed to be one of the conjugate shears of the NW- to NNW- trending sinistral Najd Shear System based on noteworthy dextral shear criteria recorded within the 620 Ma sheared granites of Numan Complex, as well as right-lateral offsets within quartz veins and dikes transected by the shear zone. The present study is an integrated field-based structural analysis and remote sensing. We utilized the ASTER data for lithologic discrimination and automatic structural lineament extraction and analysis of the Neoproterozoic basement lithologies encountered along and within the vicinity of ASZ. Various false color composite images were generated and evaluated for lithological mapping and structural lineaments. The obtained map was analyzed using GIS techniques to interpret the behavior of the existing lineaments and their spatial distribution. Based on the results of the ASTER data, two significant areas; around Bir Ad-Damm and to the south of Wadi Numan, are selected for detailed field investigation. Shear-sense indicators and overprinting relations clearly show a complicated Neoproterozoic history of ASZ, involving at least three deformations: (1) an early attenuated NE-SW sinistral shearing; followed by (2) a SE-directed thrusting phase resulted in the formation SE-verging thrusts and associated thrust-related folds; and (3) late NE-SW intensive dextral transcurrent shearing played a significant role in the creation of mesoscopic shear-zone related folds, particularly in the area near Bir Ad-Damm. Such deformation history demonstrates the same episode of Neoproterozoic deformation exhibited in the NE-trending shear zones in the Arabian-Nubian Shield (ANS).

  1. Optimal beta-ray shielding thicknesses for different therapeutic radionuclides and shielding materials

    International Nuclear Information System (INIS)

    Cho, Yong In; Kim, Ja Mee; Kim, Jung Hoon

    2017-01-01

    To better understand the distribution of deposited energy of beta and gamma rays according to changes in shielding materials and thicknesses when radionuclides are used for therapeutic nuclear medicine, a simulation was conducted. The results showed that due to the physical characteristics of each therapeutic radionuclide, the thicknesses of shielding materials at which beta-ray shielding takes place varied. Additional analysis of the shielding of gamma ray was conducted for radionuclides that emit both beta and gamma rays simultaneously with results showing shielding effects proportional to the atomic number and density of the shielding materials. Also, analysis of bremsstrahlung emission after beta-ray interactions in the simulation revealed that the occurrence of bremsstrahlung was relatively lower than theoretically calculated and varied depending on different radionuclides. (authors)

  2. Measurement of neutron energy spectra of PuO[sub 2]-UO[sub 2] mixed oxide fuel and penetrated through surrounding lead-acryl shield

    Energy Technology Data Exchange (ETDEWEB)

    Nakao, Noriaki; Tsujimura, Norio; Nakamura, Takashi (Tohoku Univ., Sendai (Japan). Cyclotron and Radioisotope Center); Momose, Takumaro; Ninomiya, Kazushige; Ishiguro; Hideharu

    1993-12-01

    The energy spectra of neutrons emitted from an aluminum can containing PuO[sub 2]-UO[sub 2] mixed oxide fuel and penetrated through a 35mm thick lead-acryl shield surrounding the can, were measured with the NE-213 organic liquid scintillator, the proton recoil proportional counter and the multi-moderator [sup 3]He spectrometer (Bonner Ball). The measured results were compared with the results calculated by the MORSE-CG Monte Carlo code on the basis of source neutron yields obtained by the ORIGEN-2 code and the source energy spectrum cited from the reference data. The agreement between these two was pretty good. The dose equivalents were then calculated from thus-obtained energy spectra and the flux-to-dose conversion factor and showed good agreement with the data measured with the neutron dose-equivalent counters (rem counters). Since the published data on energy spectrum of mixed oxide fuel are very scarce, these results can be useful as basic data for shielding design study and radiation control of nuclear fuel facilities. (author).

  3. Scatter radiation breast exposure during head CT: impact of scanning conditions and anthropometric parameters on shielded and unshielded breast dose

    Energy Technology Data Exchange (ETDEWEB)

    Klasic, B. [Hospital for pulmonary diseases, Zagreb (Croatia); Knezevic, Z.; Vekic, B. [Rudjer Boskovic Institute, Zagreb (Croatia); Brnic, Z.; Novacic, K. [Merkur Univ. Hospital, Zagreb (Croatia)

    2006-07-01

    Constantly increasing clinical requests for CT scanning of the head on our facility continue to raise concern regarding radiation exposure of patients, especially radiosensitive tissues positioned close to the scanning plane. The aim of our prospective study was to estimate scatter radiation doses to the breast from routine head CT scans, both with and without use of lead shielding, and to establish influence of various technical and anthropometric factors on doses using statistical data analysis. In 85 patient referred to head CT for objective medical reasons, one breast was covered with lead apron during CT scanning. Radiation doses were measured at skin of both breasts and over the apron simultaneously, by the use of thermo luminescent dosimeters. The doses showed a mean reduction by 37% due to lead shielding. After we statistically analyzed our data, we observed significant correlation between under-the-shield dose and values of technical parameters. We used multiple linear regression model to describe the relationships of doses to unshielded and shielded breast respectively, with anthropometric and technical factors. Our study proved lead shielding of the breast to be effective, easy to use and leading to a significant reduction in scatter dose. (author)

  4. Scatter radiation breast exposure during head CT: impact of scanning conditions and anthropometric parameters on shielded and unshielded breast dose

    International Nuclear Information System (INIS)

    Klasic, B.; Knezevic, Z.; Vekic, B.; Brnic, Z.; Novacic, K.

    2006-01-01

    Constantly increasing clinical requests for CT scanning of the head on our facility continue to raise concern regarding radiation exposure of patients, especially radiosensitive tissues positioned close to the scanning plane. The aim of our prospective study was to estimate scatter radiation doses to the breast from routine head CT scans, both with and without use of lead shielding, and to establish influence of various technical and anthropometric factors on doses using statistical data analysis. In 85 patient referred to head CT for objective medical reasons, one breast was covered with lead apron during CT scanning. Radiation doses were measured at skin of both breasts and over the apron simultaneously, by the use of thermo luminescent dosimeters. The doses showed a mean reduction by 37% due to lead shielding. After we statistically analyzed our data, we observed significant correlation between under-the-shield dose and values of technical parameters. We used multiple linear regression model to describe the relationships of doses to unshielded and shielded breast respectively, with anthropometric and technical factors. Our study proved lead shielding of the breast to be effective, easy to use and leading to a significant reduction in scatter dose. (author)

  5. Thyroid shields and neck exposures in cephalometric radiography

    International Nuclear Information System (INIS)

    Hujoel, Philippe; Hollender, Lars; Bollen, Anne-Marie; Young, John D; Cunha-Cruz, Joana; McGee, Molly; Grosso, Alex

    2006-01-01

    The thyroid is among the more radiosensitive organs in the body. The goal of this study was twofold: (1) to evaluate age-related changes in what is exposed to ionizing radiation in the neck area, and (2) to assess thyroid shield presence in cephalometric radiographs Cephalometric radiographs at one academic setting were sampled and neck exposure was related to calendar year and patient's gender and age. In the absence of shields, children have more vertebrae exposed than adults (p < 0.0001) and females have more neck tissue exposed inferior to the hyoid bone than males (p < 0.0001). The hyoid bone-porion distance increased with age (p <0.01). Thyroid shields were visible in 19% of the radiographs and depended strongly on the calendar year during which patient was seen (p-value <0.0001). Compared to adults, children were less likely to wear thyroid shields, particularly between 1973 and 1990 (1.8% versus 7.3% – p-value < 0.05) and between 2001 and 2003 (7.1% versus 42.9% – p-value < 0.05). In the absence of a thyroid shield, children have more neck structure exposed to radiation than adults. In agreement with other reports, thyroid shield utilization in this study was low, particularly in children

  6. Shielding synchrotron light sources: Advantages of circular shield walls tunnels

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, S.L. [Design and Accelerator Operations Consulting, 568 Wintergreen Ct Ridge, NY 11961 (United States); Ghosh, V.J.; Breitfeller, M. [NSLS-II, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2016-08-11

    Third generation high brightness light sources are designed to have low emittance and high current beams, which contribute to higher beam loss rates that will be compensated by Top-Off injection. Shielding for these higher loss rates will be critical to protect the projected higher occupancy factors for the users. Top-Off injection requires a full energy injector, which will demand greater consideration of the potential abnormal beam miss-steering and localized losses that could occur. The high energy electron injection beam produce significantly higher neutron component dose to the experimental floor than lower energy injection and ramped operations. High energy neutrons produced in the forward direction from thin target beam losses are a major component of the dose rate outside the shield walls of the tunnel. The convention has been to provide thicker 90° ratchet walls to reduce this dose to the beam line users. We present an alternate circular shield wall design, which naturally and cost effectively increases the path length for this forward radiation in the shield wall and thereby substantially decreasing the dose rate for these beam losses. This shield wall design will greatly reduce the dose rate to the users working near the front end optical components but will challenge the beam line designers to effectively utilize the longer length of beam line penetration in the shield wall. Additional advantages of the circular shield wall tunnel are that it's simpler to construct, allows greater access to the insertion devices and the upstream in tunnel beam line components, as well as reducing the volume of concrete and therefore the cost of the shield wall.

  7. Comparative analysis of the radiation shield effect in an abdominal CT scan

    International Nuclear Information System (INIS)

    Kim, Seon-Chil; Kim, Young-Jae; Lee, Joon-Seok; Dong, Kyung-Rae; Chung, Woon-Kwan; Lim, Chang-Seon

    2014-01-01

    This study measured and compared the dose on the eyeballs and the thyroid with and without the use of a shield by applying the abdominal examination protocol used in an actual examination to a 64-channel computed tomography (CT) scan. A dummy phantom manufactured from acryl was used to measure the dose to the eyeballs and the thyroid of a patient during a thoraco-abdominal CT scan. The dose was measured using three dosimeters (optically-stimulated luminescence dosimeter (OSLD), thermoluminescence dosimeter (TLD) and photoluminescence dosimeter (PLD)) attached to the surfaces of three parts (left and right eyeballs and thyroid) in a phantom with and without the use of a shield for the eyeballs and the thyroid. Two types of shields (1-mm barium shielding sheet and 1-mm tungsten shielding sheet) were used for the measurements. The goggles and the lead shield, which are normally used in clinical practice, were used to compare the shield ratios of the shields. According to the results of the measurements made by using the OSLD, the shield ratios of the barium and the tungsten sheets were in the range of 34 - 36%. The measurements made by using the TLD showed that the shield ratio of the barium sheet was 6.25% higher than that of the tungsten sheet. When the PLD was used for the measurement, the shield ratio of the barium sheet was 33.34%, which was equivalent to that of the tungsten sheet. These results confirmed that the cheap barium sheet had a better shielding effect than the expensive tungsten sheet.

  8. X-ray face mask and chest shield device

    International Nuclear Information System (INIS)

    Moti, S.

    1981-01-01

    A protective face mask is designed to shield an x-ray technician or machine operator primarily from random secondary or scatter x-rays deflected towards his face, head and neck by the table, walls, equipment and other reflecting elements in an x-ray room or chamber. The face mask and chest shield device can be mounted on a patient's shoulders in reverse attitude to protect the back of a patient's head and neck from the x-ray beam. The face mask is relatively or substantially transparent and contains lead in combination with a plastic ionomer or comonomer, which to a degree absorbs or resists penetration of the random deflected secondary or scatter x-rays or the x-ray beam through the mask. The face mask is removably attachable to the chest shield for easy application of the device to and support upon the shoulders of the technician or the patient. (author)

  9. INTOR radiation shielding for personnel access

    International Nuclear Information System (INIS)

    Gohar, Y.; Abdou, M.

    1981-01-01

    The INTOR reactor shield system consists of the blanket, bulk shield, penetration shield, component shield, and biological shield. The bulk shield consists of two parts: (a) the inboard shield; and (b) the outboard shield. The distinction between the different components of the shield system is essential to satisfy the different design constraints and achieve various objectives

  10. Synthesis of ferrofluid based nanoarchitectured polypyrrole composites and its application for electromagnetic shielding

    Energy Technology Data Exchange (ETDEWEB)

    Varshney, Swati [Polymeric and Soft Materials Section, National Physical Laboratory (CSIR), New Delhi 110012 (India); Department of Chemistry, Delhi Institute of Tool Engineering, Okhla, New Delhi 110020 (India); Amity Institute of Advanced Research and Studies, Materials and Devices, AIARS (M and D), Amity University, Noida, UP 201303 (India); Ohlan, Anil [Department of Physics, M.D. University, Rohtak, Haryana 124001 (India); Jain, V.K. [Amity Institute of Advanced Research and Studies, Materials and Devices, AIARS (M and D), Amity University, Noida, UP 201303 (India); Dutta, V.P. [Department of Chemistry, Delhi Institute of Tool Engineering, Okhla, New Delhi 110020 (India); Dhawan, S.K., E-mail: skdhawan@mail.nplindia.ernet.in [Polymeric and Soft Materials Section, National Physical Laboratory (CSIR), New Delhi 110012 (India)

    2014-01-15

    The monodispersion of magnetic nanoparticles in conducting polymer is the prerequisite to make a high quality composite for tunable electromagnetic interference (EMI) shielding. To meet this challenge, we have designed and synthesized ferrofluid based nanoarchitectured polypyrrole composites containing Fe{sub 3}O{sub 4} (8–12 nm) via in situ oxidative polymerization. To tune the microwave signals, polypyrrole composites (PFF) with different monomer/ferrofluid weight ratios have been prepared and characterized in microwave frequency domain. A maximum shielding effectiveness value of SE{sub A(max)} = 20.4 dB (∼99% attenuation) due to the absorption of microwave has been observed in the frequency range of 12.4–18 GHz and attenuation level varied with ferrofluid loading. The electrical conductivity of PFF composite is of the order of 10{sup −2} S cm{sup −1} order and having superparamagnetic nature with saturation magnetization (M{sub s}) of 5.5 emu g{sup −1}. The lightweight PFF composites with high attenuations can provide full control over the atomic structure and are favorable for the practical EMI shielding application for commercial electronic appliances. - Highlights: • Aqueous ferrofluid has been incorporated in polypyrrole matrix leads to PFF nanocomposites. • PFF composites shows conductivity of the order of 10{sup −2} S cm{sup −1} and saturation magnetization of 5.5 emu g{sup −1}. • Shielding effectiveness of 23.5 dB (SE{sub A} ∼ 20.4 dB and SE{sub R} ∼ 3.1 dB) has been achieved. • Shielding effectiveness depends on the ferrofluid loading.

  11. Gravitational Field Shielding by Scalar Field and Type II Superconductors

    Directory of Open Access Journals (Sweden)

    Zhang B. J.

    2013-01-01

    Full Text Available The gravitational field shielding by scalar field and type II superconductors are theoret- ically investigated. In accord with the well-developed five-dimensional fully covariant Kaluza-Klein theory with a scalar field, which unifies the Einsteinian general relativity and Maxwellian electromagnetic theory, the scalar field cannot only polarize the space as shown previously, but also flatten the space as indicated recently. The polariza- tion of space decreases the electromagnetic field by increasing the equivalent vacuum permittivity constant, while the flattening of space decreases the gravitational field by decreasing the equivalent gravitational constant. In other words, the scalar field can be also employed to shield the gravitational field. A strong scalar field significantly shield the gravitational field by largely decreasing the equivalent gravitational constant. According to the theory of gravitational field shielding by scalar field, the weight loss experimentally detected for a sample near a rotating ceramic disk at very low tempera- ture can be explained as the shielding of the Earth gravitational field by the Ginzburg- Landau scalar field, which is produced by the type II superconductors. The significant shielding of gravitational field by scalar field produced by superconductors may lead to a new spaceflight technology in future.

  12. Application of MCNP code in shielding calculation of minitype fast reactor

    International Nuclear Information System (INIS)

    He Keyu; Han Weishi

    2008-01-01

    An accurate shielding calculation model has been set up for the minitype sodium-cooled fast reactor (MFR) based on MCNP code and particular calculation of its primary shielding parameters has been carried out. The results indicate that the photon and neutron flux density of MFR has rapidly fallen to a low-level. The material for the shielding layer outside of main container is primarily of carbon steel, which can be design as a shielding structure satisfying the safety code. The sodium activation in primary circuit is extremely limited and it is simple to shield from. Both the output of helium in reflector and burn up of boron-10 in control rod are very small. These materials can be used for several cycle lives. (authors)

  13. Test of a new gonad shield in radiographic hip joint examinations of sucklings and infants

    International Nuclear Information System (INIS)

    Bronsch, T.

    1977-01-01

    Preparation and application of a shield consisting of lead rubber are described. Using the shield, a considerable decrease of radiation exposure to male and female infants could be achieved. Therefore it is recommended for application in mass examinations of hip joints. (author)

  14. GRAVITATIONAL FIELD SHIELDING AND SUPERNOVA EXPLOSIONS

    International Nuclear Information System (INIS)

    Zhang, T. X.

    2010-01-01

    A new mechanism for supernova explosions called gravitational field shielding is proposed, in accord with a five-dimensional fully covariant Kaluza-Klein theory with a scalar field that unifies the four-dimensional Einsteinian general relativity and Maxwellian electromagnetic theory. It is shown that a dense compact collapsing core of a star will suddenly turn off or completely shield its gravitational field when the core collapses to a critical density, which is inversely proportional to the square of mass of the core. As the core suddenly turns off its gravity, the extremely large pressure immediately stops the core collapse and pushes the mantle material of supernova moving outward. The work done by the pressure in the expansion can be the order of energy released in a supernova explosion. The gravity will resume and stop the core from a further expansion when the core density becomes less than the critical density. Therefore, the gravitational field shielding leads a supernova to impulsively explode and form a compact object such as a neutron star as a remnant. It works such that a compressed spring will shoot the oscillator out when the compressed force is suddenly removed.

  15. Monte Carlo-based development of a shield and total background estimation for the COBRA experiment

    International Nuclear Information System (INIS)

    Heidrich, Nadine

    2014-11-01

    The COBRA experiment aims for the measurement of the neutrinoless double beta decay and thus for the determination the effective Majorana mass of the neutrino. To be competitive with other next-generation experiments the background rate has to be in the order of 10 -3 counts/kg/keV/yr, which is a challenging criterion. This thesis deals with the development of a shield design and the calculation of the expected total background rate for the large scale COBRA experiment containing 13824 6 cm 3 CdZnTe detectors. For the development of a shield single-layer and multi-layer shields were investigated and a shield design was optimized concerning high-energy muon-induced neutrons. As the best design the combination of 10 cm boron doped polyethylene as outermost layer, 20 cm lead and 10 cm copper as innermost layer were determined. It showed the best performance regarding neutron attenuation as well as (n, γ) self-shielding effects leading to a negligible background rate of less than 2.10 -6 counts/kg/keV/yr. Additionally. the shield with a thickness of 40 cm is compact and costeffective. In the next step the expected total background rate was computed taking into account individual setup parts and various background sources including natural and man-made radioactivity, cosmic ray-induced background and thermal neutrons. Furthermore, a comparison of measured data from the COBRA demonstrator setup with Monte Carlo data was used to calculate reliable contamination levels of the single setup parts. The calculation was performed conservatively to prevent an underestimation. In addition, the contribution to the total background rate regarding the individual detector parts and background sources was investigated. The main portion arise from the Delrin support structure, the Glyptal lacquer followed by the circuit board of the high voltage supply. Most background events originate from particles with a quantity of 99 % in total. Regarding surface events a contribution of 26

  16. Monte Carlo-based development of a shield and total background estimation for the COBRA experiment

    Energy Technology Data Exchange (ETDEWEB)

    Heidrich, Nadine

    2014-11-15

    The COBRA experiment aims for the measurement of the neutrinoless double beta decay and thus for the determination the effective Majorana mass of the neutrino. To be competitive with other next-generation experiments the background rate has to be in the order of 10{sup -3} counts/kg/keV/yr, which is a challenging criterion. This thesis deals with the development of a shield design and the calculation of the expected total background rate for the large scale COBRA experiment containing 13824 6 cm{sup 3} CdZnTe detectors. For the development of a shield single-layer and multi-layer shields were investigated and a shield design was optimized concerning high-energy muon-induced neutrons. As the best design the combination of 10 cm boron doped polyethylene as outermost layer, 20 cm lead and 10 cm copper as innermost layer were determined. It showed the best performance regarding neutron attenuation as well as (n, γ) self-shielding effects leading to a negligible background rate of less than 2.10{sup -6} counts/kg/keV/yr. Additionally. the shield with a thickness of 40 cm is compact and costeffective. In the next step the expected total background rate was computed taking into account individual setup parts and various background sources including natural and man-made radioactivity, cosmic ray-induced background and thermal neutrons. Furthermore, a comparison of measured data from the COBRA demonstrator setup with Monte Carlo data was used to calculate reliable contamination levels of the single setup parts. The calculation was performed conservatively to prevent an underestimation. In addition, the contribution to the total background rate regarding the individual detector parts and background sources was investigated. The main portion arise from the Delrin support structure, the Glyptal lacquer followed by the circuit board of the high voltage supply. Most background events originate from particles with a quantity of 99 % in total. Regarding surface events a

  17. The leaded apron revisited: does it reduce gonadal radiation dose in dental radiology

    Energy Technology Data Exchange (ETDEWEB)

    Wood, R.E.; Harris, A.M.; van der Merwe, E.J.; Nortje, C.J. (Ontario Cancer Institute, Princess Margaret Hospital, Toronto (Canada))

    1991-05-01

    A tissue-equivalent anthropomorphic human phantom was used with a lithium fluoride thermoluminescent dosimetry system to evaluate the radiation absorbed dose to the ovarian and testicular region during dental radiologic procedures. Measurements were made with and without personal lead shielding devices consisting of thyroid collar and apron of 0.25 mm lead thickness equivalence. The radiation absorbed dose with or without lead shielding did not differ significantly from control dosimeters in vertex occlusal and periapical views (p greater than 0.05). Personal lead shielding devices did reduce gonadal dose in the case of accidental exposure (p less than 0.05). A leaded apron of 0.25 mm lead thickness equivalent was permeable to radiation in direct exposure testing.

  18. The leaded apron revisited: does it reduce gonadal radiation dose in dental radiology

    International Nuclear Information System (INIS)

    Wood, R.E.; Harris, A.M.; van der Merwe, E.J.; Nortje, C.J.

    1991-01-01

    A tissue-equivalent anthropomorphic human phantom was used with a lithium fluoride thermoluminescent dosimetry system to evaluate the radiation absorbed dose to the ovarian and testicular region during dental radiologic procedures. Measurements were made with and without personal lead shielding devices consisting of thyroid collar and apron of 0.25 mm lead thickness equivalence. The radiation absorbed dose with or without lead shielding did not differ significantly from control dosimeters in vertex occlusal and periapical views (p greater than 0.05). Personal lead shielding devices did reduce gonadal dose in the case of accidental exposure (p less than 0.05). A leaded apron of 0.25 mm lead thickness equivalent was permeable to radiation in direct exposure testing

  19. Debye shielding in a dusty plasma with nonextensively distributed electrons and ions

    International Nuclear Information System (INIS)

    Liu, Y.; Xu, K.; Liu, S. Q.

    2012-01-01

    The phenomenon of Debye shielding in dusty plasmas is investigated within the framework of nonextensively distributed electrons and ions. The effects of dust grain charge fluctuation are considered. It shows that the increase of the nonextensive parameters of electrons and ions will lead to the decrease of the shielding distance and it is due to that the effective temperature of nonextensively distributed particles drops with the increase of nonextensive parameters. There is a rather interesting result that the Debye shielding effects may vanish in a certain condition when the fluctuation of the dust grain charges is taken into account.

  20. Design of platform for removing screws from LCD display shields

    Science.gov (United States)

    Tu, Zimei; Qin, Qin; Dou, Jianfang; Zhu, Dongdong

    2017-11-01

    Removing the screws on the sides of a shield is a necessary process in disassembling a computer LCD display. To solve this issue, a platform has been designed for removing the screws on display shields. This platform uses virtual instrument technology with LabVIEW as the development environment to design the mechanical structure with the technologies of motion control, human-computer interaction and target recognition. This platform removes the screws from the sides of the shield of an LCD display mechanically thus to guarantee follow-up separation and recycle.

  1. Deep-penetration calculations in concrete and iron for shielding of proton therapy accelerators

    International Nuclear Information System (INIS)

    Sheu, Rong-Jiun; Chen, Yen-Fu; Lin, Uei-Tyng; Jiang, Shiang-Huei

    2012-01-01

    Proton accelerators in the energy range of approximately 200 MeV have become increasingly popular for cancer treatment in recent years. These proton therapy facilities usually involve bulky concrete or iron in their shielding design or accelerator structure. Simple shielding data, such as source terms or attenuation lengths for various proton energies and materials are useful in designing accelerator shielding. Understanding the appropriateness or uncertainties associated with these data, which are largely generated from Monte Carlo simulations, is critical to the quality of a shielding design. This study demonstrated and investigated the problems of deep-penetration calculations on the estimation of shielding parameters through an extensive comparison between the FLUKA and MCNPX calculations for shielding against a 200-MeV proton beam hitting an iron target. Simulations of double-differential neutron production from proton bombardment were validated by comparison with experimental data. For the concrete shielding, the FLUKA calculated depth–dose distributions were consistent with the MCNPX results, except for some discrepancies in backward directions. However, for the iron shielding, if FLUKA is used inappropriately then overestimation of neutron attenuation can be expected as shown by this work because of the multigroup treatment for low-energy neutrons in FLUKA. Two neutron energy group structures, three degrees of self-shielding correction, and two iron compositions were considered in this study. Significant variation of the resulting attenuation lengths indicated the importance of problem-dependent multigroup cross sections and proper modeling of iron composition in deep-penetration calculations.

  2. Evaluation of X-ray shielding performance of protective aprons

    International Nuclear Information System (INIS)

    Kumagai, Michitomo; Shintani, Mitsuo; Kuranishi, Makoto

    1999-01-01

    Lead equivalent, which offers protection against x-rays, is rated with a 100 kV tube voltage in Japanese Industrial Standard (JIS) Z 4501-1988, Testing method of lead equivalent for x-ray protective devices.'' However, the actual tube voltage in general diagnostic examinations (normal to special radiography; including computed tomography, CT) is 50 to 150 kV. Therefore, we measured whether the performance of current lead aprons (three products) and protective aprons using composite materials (two products) changes at 60 to 141 kV of tube voltage. Furthermore, we evaluated x-ray shielding performance by measuring the transmission ratio of scattered x-rays. The lead equivalent of two currently used lead aprons was almost the same at all voltages. However, in one currently used lead apron and both protective aprons made of composite materials, lead equivalent decreased rapidly when tube voltage exceeded 100 kV. The transmission ratio of scattered x-rays increased with increasing tube voltage in all of the protective aprons examined. Further, in all aprons examined, the transmission ratio of scattered x-rays declined with widening of the scatter angle. As mentioned above, the x-ray shielding performance of some x-ray protective aprons suddenly decreased at tube voltages over 100 kV. Thus the performance of x-ray protective aprons should be published, and JIS Z 4501 needs to be revised. (author)

  3. Evaluation of X-ray shielding performance of protective aprons

    Energy Technology Data Exchange (ETDEWEB)

    Kumagai, Michitomo; Shintani, Mitsuo; Kuranishi, Makoto [Toyama Medical and Pharmaceutical Univ. (Japan). Hospital

    1999-04-01

    Lead equivalent, which offers protection against x-rays, is rated with a 100 kV tube voltage in Japanese Industrial Standard (JIS) Z 4501-1988, Testing method of lead equivalent for x-ray protective devices.`` However, the actual tube voltage in general diagnostic examinations (normal to special radiography; including computed tomography, CT) is 50 to 150 kV. Therefore, we measured whether the performance of current lead aprons (three products) and protective aprons using composite materials (two products) changes at 60 to 141 kV of tube voltage. Furthermore, we evaluated x-ray shielding performance by measuring the transmission ratio of scattered x-rays. The lead equivalent of two currently used lead aprons was almost the same at all voltages. However, in one currently used lead apron and both protective aprons made of composite materials, lead equivalent decreased rapidly when tube voltage exceeded 100 kV. The transmission ratio of scattered x-rays increased with increasing tube voltage in all of the protective aprons examined. Further, in all aprons examined, the transmission ratio of scattered x-rays declined with widening of the scatter angle. As mentioned above, the x-ray shielding performance of some x-ray protective aprons suddenly decreased at tube voltages over 100 kV. Thus the performance of x-ray protective aprons should be published, and JIS Z 4501 needs to be revised. (author)

  4. Infinite slab-shield dose calculations

    International Nuclear Information System (INIS)

    Russell, G.J.

    1989-01-01

    I calculated neutron and gamma-ray equivalent doses leaking through a variety of infinite (laminate) slab-shields. In the shield computations, I used, as the incident neutron spectrum, the leakage spectrum (<20 MeV) calculated for the LANSCE tungsten production target at 90 degree to the target axis. The shield thickness was fixed at 60 cm. The results of the shield calculations show a minimum in the total leakage equivalent dose if the shield is 40-45 cm of iron followed by 20-15 cm of borated (5% B) polyethylene. High-performance shields can be attained by using multiple laminations. The calculated dose at the shield surface is very dependent on shield material. 4 refs., 4 figs., 1 tab

  5. Attenuation of Gamma Rays by Concrete . Lead Slag Composites

    International Nuclear Information System (INIS)

    Ismail, I.M.; Sweelam, M.H.; Zaghloul, Y.R.; Aly, H.F.

    2008-01-01

    Using of wastes and industrial by-products as concrete aggregate to be used as structural and radiation shielded material has increased in the recent years. Concrete was mixed with different amounts of lead slag extracted from recycling of the spent automotive batteries as fine aggregates. The lead slag was used as partial replacement of sand in the studied composites. The concrete composites obtained were characterized in terms of density, water absorption, porosity, compressive strength and attenuation of γ- rays with different energies. The attenuation coefficient and the half value thickness of the different matrices were calculated and discussed

  6. Electromagnetic shield

    International Nuclear Information System (INIS)

    Miller, J.S.

    1987-01-01

    An electromagnetic shield is described comprising: closed, electrically-conductive rings, each having an open center; and binder means for arranging the rings in a predetermined, fixed relationship relative to each other, the so-arranged rings and binder means defining an outer surface; wherein electromagnetic energy received by the shield from a source adjacent its outer surface induces an electrical current to flow in a predetermined direction adjacent and parallel to the outer surface, through the rings; and wherein each ring is configured to cause source-induced alternating current flowing through the portion of the ring closest to the outer surface to electromagnetically induce an oppositely-directed current in the portion of the ring furthest from the surface, such oppositely-directed current bucking any source-induced current in the latter ring portion and thus reducing the magnitude of current flowing through it, whereby the electromagnetic shielding effected by the shield is enhanced

  7. Structural properties of Bi2O3–B2O3–SiO2–Na2O glasses for gamma ray shielding applications

    International Nuclear Information System (INIS)

    Kaur, Kulwinder; Singh, K.J.; Anand, Vikas

    2016-01-01

    Glass samples of the xBi 2 O 3 –(0.70−x)B 2 O 3 –0.15SiO 2 –0.15Na 2 O (where x=0 up to 0.5 mol fraction) have been prepared in the laboratory by using melt quenching technique. 137 Cs source has been used for experimental measurements of mass attenuation coefficient of γ-rays at 662 keV. Mass attenuation coefficient of our glass samples has been compared with standard nuclear radiation shield “barite concrete”. It has been concluded that bismuth containing glass samples can be potential candidates for γ-ray shielding applications. Glasses must have appreciable elastic moduli values for their practical utility as γ-ray shields which are related to coordination number and non-bridging oxygens. Structural properties including coordination number and non-bridging oxygens of the structural units of the glass system have been estimated from the detailed analysis of Optical, Raman and FTIR spectra. Reported investigations can contribute to the development of transparent gamma ray shields. - Highlights: • Bi containing samples can be potential candidates as γ-ray shielding materials. • Number of non-bridging oxygens increases with the increase in the content of Bi 2 O 3 . • Coordination number of boron decreases with increase in the content of Bi 2 O 3 .

  8. Experience with a servo-hydraulic mechanical testing machine installed in a new shielded active facility at Windscale Nuclear Power Development Laboratories

    International Nuclear Information System (INIS)

    Garlick, A.; Hindmarch, P.; Gravenor, J.G.; Rhodes, D.

    1982-03-01

    An Instron model 1273 servo-hydraulic machine has been installed within a lead-shielded cell at Windscale in order to provide a facility capable of performing a wide range of mechanical tests on nuclear reactor structural materials and fuel assembly components. This particular type of machine was chosen because it has design features associated with the load frame, location of the actuator and adjustment and clamping of the cross-head that are especially well suited to remote operation within a shielded cell. The design of the testing facility is described and the programmes of work that have been completed over the past 11/2 years of operation are reviewed. (author)

  9. A study on optimization of photoneutron shielding in a medical accelerator room by using Monte Carlo simulation

    International Nuclear Information System (INIS)

    Kim, Yong Nam; Jeong, Kyoungkeun; Kim, Joo Young; Lee, Chang Geol; Seong, Jinsil; Choi, Sang Hyun; Kim, Chan Hyeong

    2008-01-01

    Medical linear accelerators operating above 10 MV require door shielding for neutrons in addition to photons. A criterion for choice of optimal configuration of lamination of BPE (Borated Polyethylene) and lead is not clear. Moreover, optimal configuration cannot be determined by the conventional method using an analytical formula and simple measurement. This study performs Monte Carlo simulation of radiation field in a commercial LINAC room with 15 MV X-ray sources. Considering two configuration of lamination such as 'lead-BPE' and 'lead-BPE-lead', dose equivalents are calculated by using the MCNPX code and comparative analyses are performed with each other. The obtained results show that there is no significant difference in neuron shielding between both configurations, whereas lead-BPE-lead is more effective for photon shielding. It is also noted that the absolute values of neutron doses are much greater than that of photon doses outside as well as inside the door, by three orders of magnitude. As a conclusion, the laminating of lead-BPE is suggested as the optimal configuration from the viewpoint of simplicity in fabrication and handling, even though it has no significant difference from lead-BPE-lead in terms of total dose equivalent. (author)

  10. RSMASS: A simple model for estimating reactor and shield masses

    International Nuclear Information System (INIS)

    Marshall, A.C.; Aragon, J.; Gallup, D.

    1987-01-01

    A simple mathematical model (RSMASS) has been developed to provide rapid estimates of reactor and shield masses for space-based reactor power systems. Approximations are used rather than correlations or detailed calculations to estimate the reactor fuel mass and the masses of the moderator, structure, reflector, pressure vessel, miscellaneous components, and the reactor shield. The fuel mass is determined either by neutronics limits, thermal/hydraulic limits, or fuel damage limits, whichever yields the largest mass. RSMASS requires the reactor power and energy, 24 reactor parameters, and 20 shield parameters to be specified. This parametric approach should be applicable to a very broad range of reactor types. Reactor and shield masses calculated by RSMASS were found to be in good agreement with the masses obtained from detailed calculations

  11. The Active Muon Shield

    CERN Document Server

    Bezshyiko, Iaroslava

    2016-01-01

    In the SHiP beam-dump of the order of 1011 muons will be produced per second. An active muon-shield is used to magnetically deflect these muons out of the acceptance of the spectrom- eter. This note describes how this shield is modelled and optimized. The SHiP spectrometer is being re-optimized using a conical decay-vessel, and utilizing the possibility to magnetize part of the beam-dump shielding iron. A shield adapted to these new conditions is presented which is significantly shorter and lighter than the shield used in the Technical Proposal (TP), while showing a similar performance.

  12. Structural and optical properties of Bi2O3-B2O3-CdO-Na2O glass system for gamma ray shielding applications

    Science.gov (United States)

    Dogra, Mridula; Singh, K. J.; Kaur, Kulwinder

    2018-05-01

    Quaternary system of the composition (0.15+x) Bi2O3-(0.55-x) B2O3-0.15CdO-0.15Na2O (where x=0, 0.1, 0.3 and 0.5 mole fraction) has been synthesized using melt-quenching technique. Gamma ray shielding properties are measured in terms of mass attenuation coefficient and half value layer at photon energies 662, 1173 and 1332 keV. These parameters are compared with standard nuclear radiation shielding `barite and ferrite' concretes. The results reflect better radiation shielding properties as compared to barite and ferrite concretes. Effective atomic number is calculated at photon energies 662 and 1173 keV. Density, molar volume and XRD studies are analyzed to know physical and structural properties of the glass system. Optical band gap, refractive index and molar refraction are calculated from UV-Visible measurements. Decrease in optical band gap and increase in molar refraction have been observed indicating the increase of non-bridging oxygens in the structure.

  13. REACTOR SHIELD

    Science.gov (United States)

    Wigner, E.P.; Ohlinger, L.E.; Young, G.J.; Weinberg, A.M.

    1959-02-17

    Radiation shield construction is described for a nuclear reactor. The shield is comprised of a plurality of steel plates arranged in parallel spaced relationship within a peripheral shell. Reactor coolant inlet tubes extend at right angles through the plates and baffles are arranged between the plates at right angles thereto and extend between the tubes to create a series of zigzag channels between the plates for the circulation of coolant fluid through the shield. The shield may be divided into two main sections; an inner section adjacent the reactor container and an outer section spaced therefrom. Coolant through the first section may be circulated at a faster rate than coolant circulated through the outer section since the area closest to the reactor container is at a higher temperature and is more radioactive. The two sections may have separate cooling systems to prevent the coolant in the outer section from mixing with the more contaminated coolant in the inner section.

  14. Digital processing of orbital radar data to enhance geologic structure - Examples from the Canadian Shield

    Science.gov (United States)

    Masuoka, Penny M.; Harris, Jeff; Lowman, Paul D., Jr.; Blodget, Herbert W.

    1988-01-01

    Various digital enhancement techniques for SAR are compared using SIR-B and Seasat images of the Canadian Shield. The three best methods for enhancing geological structure were found to be: (1) a simple linear contrast stretch; (2) a mean or median low-pass filter to reduce speckle prior to edge enhancement or a K nearest-neighbor average to cosmetically reduce speckle; and (3) a modification of the Moore-Waltz (1983) technique. Three look directions were coregistered and several means of data display were investigated as means of compensating for radar azimuth biasing.

  15. Selection and characterization of lead alloys for use in the SDC EM Calorimeter

    International Nuclear Information System (INIS)

    Nasiatka, J.

    1993-01-01

    Lead, because of it's density and ductility, has been used by man for centuries for many things ranging from building materials, to piping; from electrical connections, to radiation shielding, and batteries. However, despite it's extensive and varied use, not much is really known about it's exact physical and structural properties except in a very rudimentary way. The SDC cast lead EM Calorimeter needs to take full advantage of all the properties that the lead alloy has to offer. Hence, a very thorough and detailed understanding of the properties of the lead-absorber structure must be obtained and controlled, so that the integrity of the calorimeter is not compromised. This paper will attempt to detail a series of ongoing experiments used to characterize and define the properties of the Calcium-Tin-Lead alloys for use in the SDC cast lead electromagnetic calorimeter

  16. Gamma ray shielding characteristic of BiZnBo-SLS and PbZnBo-SLS glass

    Science.gov (United States)

    Syuhada Ahmad, Nor; Shahrim Mustafa, Iskandar; Mansor, Ishak; Malik, Muhammad Fadhirul Izwan bin Abdul; Ain Nabilah Razali, Nur; Nordin, Sufiniza

    2018-05-01

    The radiation shielding and optical properties of x [RmOn] (0.5‑x) [ZnO] 0.2 [B2O3] 0.3 [SLS], where RmOn are Bi2O3 and PbO with x = 0.05, 0.10, 0.20, 0.30, 0.40, and 0.45 have been prepared by using the melt-quenching method at 1200 °C and was investigated on their physical, structural and gamma ray shielding properties. Field-emission scanning electron microscope (FESEM) data revealed that the particle morphologies is aggregated and irregular in shapes and size. Energy dispersive x-ray spectroscopy (EDS) elemental mapping data confirmed that all mentioned element all present on the prepared glass. Soda Lime Silica (SLS) that is mainly composed of SiO2 has been utilized in this study as the source of SiO2 for fabrication of glass system. From the result, the density and molar volume of both glass samples increased as Bi2O3 and PbO content increased. The gamma ray shielding properties, such as linear attenuation and mass attenuation coefficient, were increased while half value layer (HVL) and mean free path (MFP) were decreased as the increased in Bi2O3 and PbO concentrations. It is recognized that the mass attenuation coefficient value of Bi2O3 and PbO glass are slightly different. From this study, it can be concluded that from the non-toxicity and shielding point of view, the bismuth glass is a good shield to gamma radiation as compared to lead glass.

  17. SHIELD 1.0: development of a shielding calculator program in diagnostic radiology

    International Nuclear Information System (INIS)

    Santos, Romulo R.; Real, Jessica V.; Luz, Renata M. da; Friedrich, Barbara Q.; Silva, Ana Maria Marques da

    2013-01-01

    In shielding calculation of radiological facilities, several parameters are required, such as occupancy, use factor, number of patients, source-barrier distance, area type (controlled and uncontrolled), radiation (primary or secondary) and material used in the barrier. The shielding design optimization requires a review of several options about the physical facility design and, mainly, the achievement of the best cost-benefit relationship for the shielding material. To facilitate the development of this kind of design, a program to calculate the shielding in diagnostic radiology was implemented, based on data and limits established by National Council on Radiation Protection and Measurements (NCRP) 147 and SVS-MS 453/98. The program was developed in C⌗ language, and presents a graphical interface for user data input and reporting capabilities. The module initially implemented, called SHIELD 1.0, refers to calculating barriers for conventional X-ray rooms. The program validation was performed by the comparison with the results of examples of shielding calculations presented in NCRP 147.

  18. Design of emergency shield

    International Nuclear Information System (INIS)

    Soliman, S.E.

    1993-01-01

    Manufacturing of an emergency movable shield in the hot laboratories center is urgently needed for the safety of personnel in case of accidents or spilling of radioactive materials. In this report, a full design for an emergency shield is presented and the corresponding dose rates behind the shield for different activities (from 1 mCi to 5 Ci) was calculated by using micro shield computer code. 4 figs., 1 tab

  19. Pilot-scale testing of refining process for decontamination of lead

    International Nuclear Information System (INIS)

    Davis, M.V.

    1991-01-01

    Lead at the Idaho National Engineering Laboratory (INEL) is predominantly used for radiation shielding. Lead is a hazardous material. When it becomes radioactively contaminated and can no longer be used as shielding, it becomes a mixed/hazardous radioactive waste. It is then subject to Environmental Protection Agency (EPA) regulations. The regulations require that lead be treated prior to disposal. There is no treatment process that will render lead nonhazardous nor is there a disposal site that will accept lead as a mixed waste. Decontamination of lead is the only alternative. Therefore, DOE-ID has initiated a lead management program to minimize the amount of lead waste generated at the INEL and to decontaminate existing inventories of contaminated lead

  20. Neutron shielding material

    International Nuclear Information System (INIS)

    Nodaka, M.; Iida, T.; Taniuchi, H.; Yosimura, K.; Nagahama, H.

    1993-01-01

    From among the neutron shielding materials of the 'kobesh' series developed by Kobe Steel, Ltd. for transport and storage packagings, silicon rubber base type material has been tested for several items with a view to practical application and official authorization, and in order to determine its adaptability to actual vessels. Silicon rubber base type 'kobesh SR-T01' is a material in which, from among the silicone rubber based neutron shielding materials, the hydrogen content is highest and the boron content is most optimized. Its neutron shielding capability has been already described in the previous report (Taniuchi, 1986). The following tests were carried out to determine suitability for practical application; 1) Long-term thermal stability test 2) Pouring test on an actual-scale model 3) Fire test The experimental results showed that the silicone rubber based neutron shielding material has good neutron shielding capability and high long-term fire resistance, and that it can be applied to the advanced transport packaging. (author)

  1. Electromagnetic behaviour of the shield in turbogenerators with superconducting solenoids

    International Nuclear Information System (INIS)

    Del Vecchio, P.; Veca, G.M.; Sacerdoti, G.

    1975-11-01

    The structure of turbogenerators with superconducting solenoids is analyzed and the investigation of electromagnetic behaviour of the rotating shield is presented. The cases considered are: (a) An hypothetical operation with a single phase with nominal current; (b) Steady-state operation in inverse sequence with 10% of the nominal current; (c) A step variation of the magnetic field intensity in the shield

  2. Shielding benchmark problems, (2)

    International Nuclear Information System (INIS)

    Tanaka, Shun-ichi; Sasamoto, Nobuo; Oka, Yoshiaki; Shin, Kazuo; Tada, Keiko.

    1980-02-01

    Shielding benchmark problems prepared by Working Group of Assessment of Shielding Experiments in the Research Committee on Shielding Design in the Atomic Energy Society of Japan were compiled by Shielding Laboratory in Japan Atomic Energy Research Institute. Fourteen shielding benchmark problems are presented newly in addition to twenty-one problems proposed already, for evaluating the calculational algorithm and accuracy of computer codes based on discrete ordinates method and Monte Carlo method and for evaluating the nuclear data used in codes. The present benchmark problems are principally for investigating the backscattering and the streaming of neutrons and gamma rays in two- and three-dimensional configurations. (author)

  3. Primary shield displacement and bowing

    International Nuclear Information System (INIS)

    Scott, K.V.

    1978-01-01

    The reactor primary shield is constructed of high density concrete and surrounds the reactor core. The inlet, outlet and side primary shields were constructed in-place using 2.54 cm (1 in) thick steel plates as the forms. The plates remained as an integral part of the shields. The elongation of the pressure tubes due to thermal expansion and pressurization is not moving through the inlet nozzle hardware as designed but is accommodated by outward displacement and bowing of the inlet and outlet shields. Excessive distortion of the shields may result in gas seal failures, intolerable helium gas leaks, increased argon-41 emissions, and shield cooling tube failures. The shield surveillance and testing results are presented

  4. Evaluation of the shielding integrity of end-shields in PHWR type NPPs

    International Nuclear Information System (INIS)

    Sah, B.M.L.; Ramamirtham, B.; Kutty, B.S.

    1996-01-01

    In the new plants (Narora Atomic Power Plants (NAPP) onwards) relatively higher radiation fields exist on the north and south fuelling machine (FM) vault walls of the E1 100m accessible area passages. These fields were first noticed at NAPS-1 and subsequently at NAPS-2 and KAPS-1. Such surveys done at RAPS have indicated that the fields on these walls would come out to be quite low (only 1-2 mR/h) from sources other than that arising from 41 Ar contamination. RAPS/MAPS experience pointed to adequacy of shielding of the FM vault walls and sufficient overall shielding thickness of the end-shields. Further, radiometry tests of end-shields carried out at Kaiga and RAPP 3 and 4 indicated fairly satisfactory and uniform filling of balls. Hence, incomplete filling of water column of the end-shields due to any venting problem was suspected to be one possible reason for the observed high fields in NAPS and Kakrapar Atomic Power Station (KAPS). Since the presence of high radiation fields, both neutron and gamma, is of long-term concern, a special study/measurement of radiation levels on reactor face during high power operation was undertaken. In order to compare the shielding integrity of the older (RAPS/MAPS solid plate type shielding) and newer (NAPS/KAPS steel ball-filled type) end shields, these experiments were done at MAPS-2 and NAPS-2. (author). 2 refs., 2 tabs

  5. The lithospheric shear-wave velocity structure of Saudi Arabia: Young volcanism in an old shield

    KAUST Repository

    Tang, Zheng; Julià , Jordi; Zahran, Hani; Mai, Paul Martin

    2016-01-01

    deployed by the Saudi Geological Survey (SGS). The study region, the Arabian plate, is traditionally divided into the western Arabian shield and the eastern Arabian platform: The Arabian shield itself is a complicated mélange of crustal material, composed

  6. Neutron shielding studies on an advanced molten salt fast reactor design

    International Nuclear Information System (INIS)

    Merk, Bruno; Konheiser, Jörg

    2014-01-01

    Highlights: • Material damage due to irradiation has already been discovered at the MSRE. • Neutronic analysis of MSFR with curved blanket wall geometry. • Neutron fluence limit at the wall of the outer vessel can be kept for 80 years. • Shielded MSFR core will be of same dimension than a SFR core. - Abstract: The molten salt reactor technology has gained some new interest. In contrast to the historic molten salt reactors, the current projects are based on designing a molten salt fast reactor. Thus the shielding becomes significantly more challenging than in historic concepts. One very interesting and innovative result of the most recent EURATOM project on molten salt reactors – EVOL – is the fluid flow optimized design of the inner reactor vessel using curved blanket walls. The developed structure leads to a very uniform flow distribution. The design avoids all internal structures. Based on this new geometry a model for neutron physics calculation is presented. The major steps are: the modeling of the curved geometry in the unstructured mesh neutron transport code HELIOS and the determination of the real neutron flux and power distribution for this new geometry. The developed model is then used for the determination of the neutron fluence distribution in the inner and outer wall of the system. Based on these results an optimized shielding strategy is developed for the molten salt fast reactor to keep the fluence in the safety related outer vessel below expected limit values. A lifetime of 80 years can be assured, but the size of the core/blanket system will be comparable to a sodium cooled fast reactor. The HELIOS results are verified against Monte-Carlo calculations with very satisfactory agreement for a deep penetration problem

  7. Thermophysical Properties of Heat Resistant Shielding Material

    International Nuclear Information System (INIS)

    Porter, W.D.

    2004-01-01

    This project was aimed at determining thermal conductivity, specific heat and thermal expansion of a heat resistant shielding material for neutron absorption applications. These data are critical in predicting the structural integrity of the shielding under thermal cycling and mechanical load. The measurements of thermal conductivity and specific heat were conducted in air at five different temperatures (-31 F, 73.4 F, 140 F, 212 F and 302 F). The transient plane source (TPS) method was used in the tests. Thermal expansion tests were conducted using push rod dilatometry over the continuous range from -40 F (-40 C) to 302 F (150 C)

  8. Activation of the concrete in the bio shield of ITER

    International Nuclear Information System (INIS)

    Kalcheva, S.

    2005-02-01

    Calculations of neutron spectra in different parts of the tokamak building of ITER are performed. A computational geometry model of the tokamak building is prepared using MCNP-4C. The model includes adequate material composition and geometry description of the main parts of the tokamak for PPCS plant model A: toroidal field coils, vacuum vessel, shield, blanket structure, first wall, divertor, 14.1 MeV neutron source. The design and the dimensions of the bio shield are taken from the current ITER design. MCNP calculations of the neutron spectra in the bio shield (concrete) of ITER are performed, using the neutron spectra in TF coils calculated at UKAEA as external neutron source. The neutron spectra in the concrete calculated by MCNP are used as input data in the code EASY99 for estimations of the activation of the concrete in the bio shield around the tokamak. The time evolutions of the maximum (in the bio shield floor) and minimum (in the bio shield side walls) specific activity (Bq/kg) and dose rate (Sv/h.) of the main dominant nuclides in the concrete are evaluated and compared for 3 different concrete types, used as biological shield in the PWR and BR3 reactors. (author)

  9. Optimisation of structural shielding of accelerator control room for compliance with ALARA principle under Indian conditions

    International Nuclear Information System (INIS)

    Ahmad, Masood; Singh, Brijesh

    1999-01-01

    The case of a 20 MV x-ray accelerator has been considered in this paper for optimisation. An internationally recommended value of α = US$ 1000 per person-sievert has been assumed. Cost of concrete has been assumed as US$ 82.7/m 3 . It is seen that, extra shielding is needed to satisfy the ALARA principle. Further, the amount of requisite shielding increases with the degree of occupancy and, also, if the local construction materials or the labour are cheaper than considered in this paper. Accordingly 1.5 to 4.75 HVLs may be needed as extra shielding in different situations. Therefore, a site specific and installation specific optimisation of shielding is necessary

  10. Shielding of the patient's gonads during intramedullary interlocking femoral nailing

    Energy Technology Data Exchange (ETDEWEB)

    Kwong, L.M.; Johanson, P.H.; Zinar, D.M.; Lenihan, M.R.; Herman, M.W. (Harbor/Univ. of California, Los Angeles Medical Center, Torrance (USA))

    1990-12-01

    Levels of exposure to radiation were recorded at sixty sites in fifteen patients during intramedullary interlocking femoral nailing. Radiation film dosimeters were placed at four gonadal sites on each subject. A standard male-gonad cup or a pelvic drape of 0.5-millimeter-thick lead-equivalent was put in place to shield the gonads. A second set of four dosimeters was placed external to the shield to approximate unprotected exposure. The total duration of the fluoroscopy averaged five minutes (range, thirty seconds to fourteen minutes). The total exposure to radiation external to the shield was 35 +/- 34 millirems at the male gonadal sites and 17 +/- 11 millirems at the female gonadal sites. With use of the gonadal shield, exposure to radiation was not measurable in thirteen of the fifteen patients. The differences between the exposures of the shielded and unshielded sites to radiation were statistically significant (p less than 0.001). The highest level of gonadal exposure was found with the treatment of proximal femoral fractures and with the use of statically locked nails. Regardless of the conditions, and for all types of fractures and locations, our results demonstrated that gonadal shielding is justified.

  11. Shielding in experimental areas

    International Nuclear Information System (INIS)

    Stevens, A.; Tarnopolsky, G.; Thorndike, A.; White, S.

    1979-01-01

    The amount of shielding necessary to protect experimental detectors from various sources of background radiation is discussed. As illustrated an experiment has line of sight to sources extending approx. 90 m upstream from the intersection point. Packing a significant fraction of this space with shielding blocks would in general be unacceptable because primary access to the ring tunnel is from the experimental halls. (1) From basic machine design considerations and the inherent necessity to protect superconducting magnets it is expected that experimental areas in general will be cleaner than at any existing accelerator. (2) Even so, it will likely be necessary to have some shielding blocks available to protect experimental apparatus, and it may well be necessary to have a large amount of shielding available in the WAH. (3) Scraping will likely have some influence on all halls, and retractable apparatus may sometimes be necessary. (4) If access to any tunnel is needed to replace a magnet, one has 96 h (4 days) available to move shielding away to permit access without additional downtime. This (the amount of shielding one can shuffle about in 96 h) is a reasonable upper limit to shielding necessary in a hall

  12. Estimation of Shielding Thickness for a Prototype Department of Energy National Spent Nuclear Fuel Program Transport Cask

    Energy Technology Data Exchange (ETDEWEB)

    SANCHEZ,LAWRENCE C.; MCCONNELL,PAUL E.

    2000-07-01

    Preliminary shielding calculations were performed for a prototype National Spent Nuclear Fuel Program (NSNFP) transport cask. This analysis is intended for use in the selection of cask shield material type and preliminary estimate of shielding thickness. The radiation source term was modeled as cobalt-60 with radiation exposure strength of 100,000 R/hr. Cobalt-60 was chosen as a surrogate source because it simultaneous emits two high-energy gammas, 1.17 MeV and 1.33 MeV. This gamma spectrum is considered to be large enough that it will upper bound the spectra of all the various spent nuclear fuels types currently expected to be shipped within the prototype cask. Point-kernel shielding calculations were performed for a wide range of shielding thickness of lead and depleted uranium material. The computational results were compared to three shielding limits: 200 mrem/hr dose rate limit at the cask surface, 50 mR/hr exposure rate limit at one meter from the cask surface, and 10 mrem/hr limit dose rate at two meters from the cask surface. The results obtained in this study indicated that a shielding thickness of 13 cm is required for depleted uranium and 21 cm for lead in order to satisfy all three shielding requirements without taking credit for stainless steel liners. The system analysis also indicated that required shielding thicknesses are strongly dependent upon the gamma energy spectrum from the radiation source term. This later finding means that shielding material thickness, and hence cask weight, can be significantly reduced if the radiation source term can be shown to have a softer, lower energy, gamma energy spectrum than that due to cobalt-60.

  13. Effectiveness of construction materials and some minerals used as radiation shielding

    International Nuclear Information System (INIS)

    Khunarak, P.; Bunnak, S.

    1988-01-01

    There are many kinds of ores in Thailand, some large amount of them are cheap and easy to obtain possess shielding properties for gamma radiation. These ores are baryte, illmenite, galena, scheelite, wolframite pyrite, cerrusite. Besides, building structure materials are also introduced for shielding properties study by using Co-60, Cs-137 and Ra-226 as gamma radiation sources in the experiments. The results turn out that those high density ores will possess a better shielding property than the low density ores. Radiation measurement equipment is G.M. tube connected to rate meter

  14. Radiologically contaminated lead shot reuse at the Idaho National Engineering Laboratory (INEL)

    International Nuclear Information System (INIS)

    Heileson, W.M.; Grant, R.P.

    1995-01-01

    This project involved the utilization of radioactively contaminated lead shot located at the Radioactive Waste Management Complex (RWMC) for radiation shielding on a radioactive liquid process tank located at Argonne National Laboratory-West (ANL-W). The use of previously contaminated shot precludes the radioactive contamination of clean shot. With limited treatment and disposal options for contaminated lead shot, the reuse of lead for shielding is significant due to the inherent characteristic of becoming a mixed waste when radiologically contaminated. The INEL conducted a lead cleanup campaign in 1990. This was designed to ensure control of potential Resource Conservation and Recovery Act (RCRA) regulated waste. Contaminated lead from throughout the INEL, was containerized per the lead Waste Acceptance Criteria at the generator sites. Limited areas at the INEL are designated for mixed waste storage. As a result, some of the lead was stored at the RWMC in the air support weather shield (ASWS). This lead was contaminated with small amounts of fission product contamination. The lead was in the form of shot, brick, sheet, casks, and other various sized pieces. In 1993, ANL-W identified a need for lead shot to be used as shielding in a radioactive liquid waste storage and processing tank at the Fuel Cycle Facility (FCF). The contaminated lead used on this project had been in storage as mixed waste at the RWMC. This paper will focus on the processes and problems encountered to utilize the contaminated lead shot

  15. Shielding factors for vehicles to gamma radiation from activity deposited on structures and ground surfaces

    International Nuclear Information System (INIS)

    Lauridsen, B.; Hedemann Jensen, P.

    1982-04-01

    This report describes a measuring procedure for the determination of shielding factors for vehicles passing through areas that have been contaminated by activity released to the atmosphere from a reactor accident. A simulated radiation field from fallout has been approximated by a point source that has been placed in a matrix around and above the vehicle. Modifying factors are discussed such as mutual shielding by nearby buildings and passengers. From measurements on different vehicles with and without passengers shielding factors are recommended for ordinary cars and busses in both urban and open areas, and areas with single family houses. (author)

  16. Dynamic Open-Rotor Composite Shield Impact Test Report

    Science.gov (United States)

    Seng, Silvia; Frankenberger, Charles; Ruggeri, Charles R.; Revilock, Duane M.; Pereira, J. Michael; Carney, Kelly S.; Emmerling, William C.

    2015-01-01

    The Federal Aviation Administration (FAA) is working with the European Aviation Safety Agency to determine the certification base for proposed new engines that would not have a containment structure on large commercial aircraft. Equivalent safety to the current fleet is desired by the regulators, which means that loss of a single fan blade will not cause hazard to the aircraft. NASA Glenn and Naval Air Warfare Center (NAWC) China Lake collaborated with the FAA Aircraft Catastrophic Failure Prevention Program to design and test a shield that would protect the aircraft passengers and critical systems from a released blade that could impact the fuselage. This report documents the live-fire test from a full-scale rig at NAWC China Lake. NASA provided manpower and photogrammetry expertise to document the impact and damage to the shields. The test was successful: the blade was stopped from penetrating the shield, which validates the design analysis method and the parameters used in the analysis. Additional work is required to implement the shielding into the aircraft.

  17. Program for photon shielding calculations. Examination of approximations on irradiation geometries

    International Nuclear Information System (INIS)

    Isozumi, Yasuhito; Ishizuka, Fumihiko; Miyatake, Hideo; Kato, Takahisa; Tosaki, Mitsuo

    2004-01-01

    Penetration factors and related numerical data in 'Manual of Practical Shield Calculation of Radiation Facilities (2000)', which correspond to the irradiation geometries of point isotropic source in infinite thick material (PI), point isotropic source in finite thick material (PF) and vertical incident to finite thick material (VF), have been carefully examined. The shield calculation based on the PI geometry is usually performed with effective dose penetration factors of radioisotopes given in the 'manual'. The present work cleary shows that such a calculation may lead to an overestimate more than twice larger, especially for thick shield of concrete and water. Employing the numerical data in the 'manual', we have fabricated a simple computer program for the estimation of penetration factors and effective doses of radioisotopes in the different irradiation geometries, i.e., PI, PF and VF. The program is also available to calculate the effective dose from a set of radioisotopes in the different positions, which is necessary for the γ-ray shielding of radioisotope facilities. (author)

  18. Utilization of recycled cathode ray tubes glass in cement mortar for X-ray radiation-shielding applications

    International Nuclear Information System (INIS)

    Ling, Tung-Chai; Poon, Chi-Sun; Lam, Wai-Shung; Chan, Tai-Po; Fung, Karl Ka-Lok

    2012-01-01

    Highlights: ► It is feasible to use recycled CRT glass in mortar as shield against X-ray radiation. ► Shielding properties of CRT mortar is strongly depended on CRT content. ► Linear attenuation coefficient was reduced by 142% upon 100% CRT glass in mortar. ► Effect of mortar thickness and irradiation energies on shielding was investigated. - Abstract: Recycled glass derived from cathode ray tubes (CRT) glass with a specific gravity of approximately 3.0 g/cm 3 can be potentially suitable to be used as fine aggregate for preparing cement mortars for X-ray radiation-shielding applications. In this work, the effects of using crushed glass derived from crushed CRT funnel glass (both acid washed and unwashed) and crushed ordinary beverage container glass at different replacement levels (0%, 25%, 50%, 75% and 100% by volume) of sand on the mechanical properties (strength and density) and radiation-shielding performance of the cement–sand mortars were studied. The results show that all the prepared mortars had compressive strength values greater than 30 MPa which are suitable for most building applications based on ASTM C 270. The density and shielding performance of the mortar prepared with ordinary crushed (lead-free) glass was similar to the control mortar. However, a significant enhancement of radiation-shielding was achieved when the CRT glasses were used due to the presence of lead in the glass. In addition, the radiation shielding contribution of CRT glasses was more pronounced when the mortar was subject to a higher level of X-ray energy.

  19. Eye-lens bismuth shielding in paediatric head CT: artefact evaluation and reduction

    International Nuclear Information System (INIS)

    Raissaki, Maria; Perisinakis, Kostas; Damilakis, John; Gourtsoyiannis, Nicholas

    2010-01-01

    CT scans of the brain, sinuses and petrous bones performed as the initial imaging test for a variety of indications have the potential to expose the eye-lens, considered among the most radiosensitive human tissues, to a radiation dose. There are several studies in adults discussing the reduction of orbital dose resulting from the use of commercially available bismuth-impregnated latex shields during CT examinations of the head. To evaluate bismuth shielding-induced artefacts and to provide suggestions for optimal eye-lens shielding in paediatric head CT. A bismuth shield was placed over the eyelids of 60 consecutive children undergoing head CT. Images were assessed for the presence and severity of artefacts with regard to eye-shield distance and shield wrinkling. An anthropomorphic paediatric phantom and thermoluminescence dosimeters (TLDs) were used to study the effect of eye lens-to-shield distance on shielding efficiency. Shields were tolerated by 56/60 children. Artefacts were absent in 45% of scans. Artefacts on orbits, not affecting and affecting orbit evaluation were noted in 39% and 14% of scans, respectively. Diagnostically insignificant artefacts on intracranial structures were noted in 1 case (2%) with shield misplacement. Mean eye-lens-to-shield distance was 8.8 mm in scans without artefacts, and 4.3 mm and 2.2 mm in scans with unimportant and diagnostically important artefacts, respectively. Artefacts occurred in 8 out of 9 cases with shield wrinkling. Dose reduction remained unchanged for different shield-to-eye distances. Bismuth shielding-related artefacts occurring in paediatric head CT are frequent, superficial and diagnostically insignificant when brain pathology is assessed. Shields should be placed 1 cm above the eyes when orbital pathology is addressed. Shield wrinkling should be avoided. (orig.)

  20. A new technique for radiation shielding in superficial X-ray therapy

    International Nuclear Information System (INIS)

    Baily, B.; Coe, M.A.; Hearnden, T.M.

    1981-01-01

    A new technique is described for making face shields for superficial X-ray therapy of small lesions located near sharp face contour changes. A ''Darvic'' shell is first vacuum-formed on a plaster cast. A low-melting-point alloy is then finely sprayed on to the shell. The area to be treated is cut out of the alloy mask and Darvic shell. Four alloys of varying melting point and varying lead and/or tin content were tested: MCP 69, MCP 70 and MCP 124 alloys afforded better shielding over the whole energy range than MCP 137. This technique of spraying masks produces a perfectly fitting shield, it is quick to make and is cheap because the mask can be recycled once treatment is finished. (U.K.)

  1. Evaluation of the Shielding Performance for the Hot-cell built in 100-MeV Isotope Beam-line of KOMAC

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jeong Min; Park, Sung Kyun; Min, Yi Sub; Cho, Yong Sub [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    This study describes the structure of the hot-cell constructed in KOMAC for radioisotope production and evaluates the shielding performance for the hot-cell via the radiation shielding ability test. Korea multi-purpose accelerator complex (KOMAC) is currently operating 20-MeV and 100-MeV beam-line one by on. Additional 100-MeV beam-line and target room (TR101) are planned for the purpose of the radioisotope production in this year. The initial goal of the radioisotope production is to produce the radioactive isotopes, Sr-82 or Cu-67, used widely for the diagnosis and treatment of the cancer. In order to produce these radioisotopes mentioned, the proton beam with the energy between 70-MeV and 100- MeV at a beam current of 300 μA is irradiated into a solid target made of ZnO or RbCl. After the irradiation of the proton beam during approximately 100 hours, the radioisotope Sr-82 with the radioactivity amount of about 3.8 Ci or the Cu-67 with the amount of about 2.7 Ci will be produced. Radioisotopes produced though this process should be conveyed from the TR101 target room to the PR101 processing room and then in order to be delivered into the place for the next process step, a hot-cell is necessary. Result of the shielding performance evaluation of the hot-cell for producing radioisotopes shows the necessity of the shield reinforcement using lead material at side of the lead glass window.

  2. Benchmarks for evaluation of shielding calculations

    International Nuclear Information System (INIS)

    Coelho, P.R.P.; Maiorino, J.R.

    1989-01-01

    The spatial-energy neutron distribution emerging from a laminated shielding (stainless, polyethylene and lead) were measured by a fast neutron spectrometer and some experimental results were compared with those calculated by a network of codes. The source neutrons incident in the shielding were 14 MeV neutrons from a H-3(d,n)He-4 reaction coming from a Van de Graaff accelerator. Experimentally was verified a good radial symmetry of neutron energy-spectrum, and also a moderation and attenuation effect for points located out of the central axis of symmetry. These results indicate that the experiment can be well modelated by R-Z geometry. A neutron-energy spectra calculated by DOT 3.5 was compared with the measured spectra, showing a good agreement in the shape and value of the spectra (12% for an integrated spectrum from 2 to 16 MeV). (author) [pt

  3. Upper mantle structure under western Saudi Arabia from Rayleigh wave tomography and the origin of Cenozoic uplift and volcanism on the Arabian Shield

    Energy Technology Data Exchange (ETDEWEB)

    Park, Y; Nyblade, A; Rodgers, A; Al-Amri, A

    2007-11-09

    The shear velocity structure of the shallow upper mantle beneath the Arabian Shield has been modeled by inverting new Rayleigh wave phase velocity measurements between 45 and 140 s together with previously published Rayleigh wave group velocity measurement between 10 and 45 s. For measuring phase velocities, we applied a modified array method that minimizes the distortion of raypaths by lateral heterogeneity. The new shear velocity model shows a broad low velocity region in the lithospheric mantle across the Shield and a low velocity region at depths {ge} 150 km localized along the Red Sea coast and Makkah-Madinah-Nafud (MMN) volcanic line. The velocity reduction in the upper mantle corresponds to a temperature anomaly of {approx}250-330 K. These finding, in particular the region of continuous low velocities along the Red Sea and MMN volcanic line, do not support interpretations for the origin of the Cenozoic plateau uplift and volcanism on the Shield invoking two separate plumes. When combined with images of the 410 and 660 km discontinuities beneath the southern part of the Arabian Shield, body wave tomographic models, a S-wave polarization analysis, and SKS splitting results, our new model supports an interpretation invoking a thermal upwelling of warm mantle rock originating in the lower mantle under Africa that crosses through the transition zone beneath Ethiopia and moves to the north and northwest under the eastern margin of the Red Sea and the Arabian Shield. In this interpretation, the difference in mean elevation between the Platform and Shield can be attributed to isostatic uplift caused by heating of the lithospheric mantle under the Shield, with significantly higher region along the Red Sea possibly resulting from a combination of lithosphere thinning and dynamic uplift.

  4. Self Shielding in Nuclear Fissile Assay Using LSDS

    International Nuclear Information System (INIS)

    Lee, Yong Deok; Park, Chang Je; Park, Geun Il; Song, Kee Chan

    2012-01-01

    The new technology for isotopic fissile material contents assay is under development at KAERI using lead slowing down spectrometer(LSDS). LSDS is very sensitive to distinguish fission signals from each fissile isotope in spent and recycled fuel. The accumulation of spent fuel is current big issue. The amount of spent fuels will reach the maximum storage capacity of the pools soon. Therefore, an interim storage must be searched and it should be optimized in design by applying accurate fissile content. When the storage has taken effect, all the nuclear materials must be also specified and verified for safety, economics and management. Generally, the spent fuel from PWR has unburned ∼1 % U235, produced ∼0.5 % plutonium from decay chain, ∼3 % fission products, ∼ 0.1 % minor actinides (MA) and uranium remainder. About 1.5 % fissile materials still exist in the spent fuel. Therefore, for reutilization of fissile materials in spent fuel at SFR, resource material is produced through pyro process. Fissile material contents in resource material must be analyzed before fabricating SFR fuel for reactor safety and economics. In assay of fissile content of spent fuel and recycled fuel, intense radiation background gives limitation on the direct analysis of fissile materials. However, LSDS is not influenced by such a radiation background in fissile assay. Based on the decided geometry setup, self shielding parameter was calculated at the fuel assay zone by introducing spent fuel or pyro produced nuclear material. When nuclear material is inserted into the assay area, the spent fuel assembly or pyro recycled fuel material perturbs the spatial distribution of the slowing down neutrons in lead and the prompt fast fission neutrons produced by fissile materials are also perturbed. The self shielding factor is interpreted as that how much of absorption is created inside the fuel area when it is in the lead. Self shielding effect provides a non-linear property in the isotopic

  5. Concrete shielding for nuclear ship 'Mutsu'

    International Nuclear Information System (INIS)

    Nagase, Tetsuo; Saito, Tetsuo

    1983-01-01

    The repair works of the shielding for the nuclear ship ''Mutsu'' were completed in August, 1982. For the primary shielding, serpentine concrete was adopted as it contains a large quantity of water required for neutron shielding, and in the secondary shielding at the upper part of the reactor containment vessel, the original shielding was abolished, and the heavy concrete (high water content, high density concrete) which is effective for neutron and gamma-ray shielding was newly adopted. In this report, the design and construction using these shielding concrete are outlined. In September, 1974, Mutsu caused radiation leak during the test, and the cause was found to be the fast neutrons streaming through a gap between the reactor pressure vessel and the primary shielding. The repair works were carried out in the Sasebo Shipyard. The outline of the repair works of the shielding is described. The design condition for the shielding, the design standard for the radiation dose outside and inside the ship, the method of shielding analysis and the performance required for shielding concrete are reported. The selection of materials, the method of construction and mixing ratio, the evaluation of the soundness and properties of concrete, and the works of placing the shielding concrete are outlined. (Kako, I.)

  6. SHIELDS Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Jordanova, Vania Koleva [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-10-03

    Predicting variations in the near-Earth space environment that can lead to spacecraft damage and failure, i.e. “space weather”, remains a big space physics challenge. A new capability was developed at Los Alamos National Laboratory (LANL) to understand, model, and predict Space Hazards Induced near Earth by Large Dynamic Storms, the SHIELDS framework. This framework simulates the dynamics of the Surface Charging Environment (SCE), the hot (keV) electrons representing the source and seed populations for the radiation belts, on both macro- and micro-scale. In addition to using physics-based models (like RAM-SCB, BATS-R-US, and iPIC3D), new data assimilation techniques employing data from LANL instruments on the Van Allen Probes and geosynchronous satellites were developed. An order of magnitude improvement in the accuracy in the simulation of the spacecraft surface charging environment was thus obtained. SHIELDS also includes a post-processing tool designed to calculate the surface charging for specific spacecraft geometry using the Curvilinear Particle-In-Cell (CPIC) code and to evaluate anomalies' relation to SCE dynamics. Such diagnostics is critically important when performing forensic analyses of space-system failures.

  7. Characterization of dynamic loads on the LMFBR rotating shield

    International Nuclear Information System (INIS)

    Morris, E.

    1979-01-01

    The rotating shields structure is a potential weak point of some current designs of primary containment against postulated whole core explosions. The calculation of the effect of transient loads on this structure, resulting from such an explosion, is therefore important in developing a safety case. The transient loads are usually calculated by computer codes such as ASTARTE, SEURBNUK, REXCO or ICECO and the effect of these loads on the structure by a suitable finite element code. Such procedure can be lengthly and costly. The present paper proposed a procedure which allows the consequences of changes in the transient loads, resulting from design changes for example, to be quickly and simply gauged. The load-impulse method of characterizing dynamic response of a structural system is well established. Provided loads with a similar temporal variation are compared, it can be shown that the dynamic response depends on only two features of the load, an average load and a time intregrated load or impulse. The scope of this approach has been extended by Youngdahl who has shown, for structures which deform in a rigid-plastic manner, that complex laoding histories can be equated to a rectangular form of loading, in a precise manner for simple structures and in an approximate manner for more complicated structures. This paper proposes that the failure characteristics of the rotating shields for which extensive plastic deformation is involved, be calculated for rectangular type loadings. The complex transient loadings calculated for various explosions and various changes in the primary vessel design can then be reduced to an equivalent rectangular form and the consequencial response of the shields structure deduced. (orig.)

  8. Neoproterozoic structural evolution of the NE-trending Ad-Damm Shear Zone, Arabian Shield, Saudi Arabia

    Science.gov (United States)

    Hamimi, Zakaria; El-Sawy, El-Sawy K.; El-Fakharani, Abdelhamid; Matsah, Mohamed; Shujoon, Abdulrahman; El-Shafei, Mohamed K.

    2014-11-01

    The Ad-Damm Shear Zone (AdSZ) is a major NE- (to NNE-) trending fault zone separating Jiddah and Asir tectonic terranes in the Neoproterozoic Juvenile Arabian Shield (AS). AdSZ is characterized by the development of dextral transcurrent shear-sense indicators and moderately to steeply NW plunging stretching lineations. It is mainly developed under high amphibolite-to greenschist-facies conditions and extends ∼380 km, with an average width ∼2-4 km, from the conspicuous Ruwah Fault Zone in the eastern shield to the Red Sea Coastal plain. It was believed to be one of the conjugate shears of the NW- to NNW-trending sinistral Najd Shear System. This assumption is, based on the noteworthy dextral shear criteria recorded within the 620 Ma mylonitic granite of No'man Complex. A total shear-zone strike length exceeding 117 km is carefully investigated during this study to reconstruct its structural evolution. Shear-sense indicators and other field observations including overprinting relations clearly demonstrate a complicated Neoproterozoic history of AdSZ, involving at least three phases of deformations (D1-D3). Both D1 and D2 phases were of contractional regime. During D1 phase a NW-SE compression led to the formation of NE-oriented low-angle thrusts and tight-overturned folds. D2 is represented by a NE-SW stress oriented that led to the development of an open folding. D3 is expressed by the NE-SW intensive dextral transcurrent brittle-ductile shearing. It is overprinting the early formed fabrics and played a significant role in the creation of AdSZ and the mega-scale related folds. Such deformation history reflects the same Neoproterozoic deformation regime recognized in the NE-trending shear zones in the Arabian-Nubian Shield (ANS).

  9. Fabrication of the full scale separable first wall of ITER shielding blanket

    International Nuclear Information System (INIS)

    Kosaku, Yasuo; Kuroda, Toshimasa; Hatano, Toshihisa; Enoeda, Mikio; Miki, Nobuharu; Akiba, Masato

    2002-10-01

    Shielding blanket for ITER-FEAT applies the unique first wall structure which is separable from the shield block for the purpose of radio-active waste reduction in the maintenance work and cost reduction in fabrication process. Also, it is required to have various types of slots in both of the first wall and the shield block, to reduce the eddy current for reduction of electro-magnetic force in disruption events. Such unique features of blanket structure required technological clarification from the technical base of the previous achievement of the blanket module fabrication development. Previously, within the EDA Task T216+, a prototype for the no.4 Primary Wall Module of the ITER Shield Blanket with integrated first wall has been manufactured by forging and drilling and the first wall has been manufactured and joined to the shield block by Hot Isostatic Pressing (HIP) in one step process. This work has been performed to clarify the remaining R and D issues which have not been covered in the previous R and D. This report summarizes the demonstrative fabrication of the real scale separable first wall for ITER shielding blanket designed for ITER-FEAT, together with the essential technology developments such as, the slit grooving of the first wall with beryllium armor and SS shield block and fabrication of a partial mockup of beryllium armored first wall panel with built-in cooling channels. This work has been performed under the task agreement of G 16 TT 95 FJ (T420-1) in ITER Engineering Design Activity Extension Period. By the demonstration of the Be armor joining to the first wall panel, the joining technique of Be and DSCu developed previously, was shown to be applicable to the realistic structure of first wall panel. Also, the slit grooving by an end-mill method and an electron discharge machining method have been applied to the first wall mockup with Be armor tiles and demonstrated the applicability within the design tolerance. As the slit grooving technique

  10. Shielding container

    International Nuclear Information System (INIS)

    Darling, K.A.M.

    1981-01-01

    A shielding container incorporates a dense shield, for example of depleted uranium, cast around a tubular member of curvilinear configuration for accommodating a radiation source capsule. A lining for the tubular member, in the form of a close-coiled flexible guide, provides easy replaceability to counter wear while the container is in service. Container life is extended, and maintenance costs are reduced. (author)

  11. Analysis of ferromagnetic shielding of the ITER NBI

    International Nuclear Information System (INIS)

    Roccella, M.; Lucca, F.; Roccella, R.; Cocilovo, V.; Ramogida, G.; Portone, A.; Tanga, A.; Formisano, A.; Martone, R.

    2006-01-01

    In ITER two heating and one diagnostic Neutral Beam Injectors (NBIs) are foreseen [P. L. Mondino et al., ''ITER neutral beam system '', Nucl. Fus., vol. 40, p. 501 (2000)]. Inside these components there are very stringent limits on the magnetic field (the flux density must be below some Gauss (G) along the ion path and below 20 G in the neutralizing region). To achieve these performances in an environment with high stray field due to the plasma and the poloidal field coils, both passive and active shielding systems are foreseen. The present design of the Magnetic Field Reduction System (MFRS) is made of seven active coils and of a box surrounding the NBI region, consisting of ferromagnetic plates 15 cm thick. The electromagnetic analysis of the effectiveness of these shields has been performed by a full 3D FEM model using the ANSYS code. To perform the FEM modeling of the component special care has been used to face the particular geometrical features of the component (a box of about 15 x 5 x 5 m vs. a ferromagnetic layer of only 15 cm thick). To insert an adequate number of FEM elements (at least 5) in the thickness of the ferromagnetic layer, without a prohibitive increase in the total FEM elements number, a particular modeling approach (a sort of '' Chinese boxes '' technique) has been developed. Due to this technique the FEM model enclosing the ferromagnetic box results completely independent on the fine FEM structure inside the shielding layer. It has been even possible, using this technique, introducing a thin (below 1 cm thick) slot all through the shielding plates, without perturbing the rest of the model. This slot has been used to analyze the effects of possible manufacturing lacks on the residual magnetic field inside the component. This technique has allowed the use of only structured meshes made by brick elements, much more accurate than the tetra elements, needed in the usual free meshing techniques. To have the possibility of changing the shielding

  12. Pros and cons of organ shielding for CT imaging

    International Nuclear Information System (INIS)

    Samei, Ehsan

    2014-01-01

    With the increased importance of CT radiation dose to health care providers, patients and the general public, there is an increased responsibility to minimize patient dose effectively. Bismuth shields offer a simple strategy to reduce dose to certain anterior radiosensitive organs such as breasts and eyes. However, in order to reduce organ dose they must be used properly; improper use can lead to an actual increase in the patient dose. They also create a proportional increase in image noise in the section of the body adjacent to the shield and further reduce the quantitative precision of CT numbers. In addition, shielding can degrade the overall efficiency (by an order of approximately 10%) of the imaging process, reducing the theoretical image quality that can be expected from a certain level of patient dose. However, in spite of their significant disadvantages, there are certain clinical situations and practice considerations that provide qualified justification for their continued use. (orig.)

  13. Technical Requirements for Fabrication and Installation of Removable Shield for CNRF in HANARO

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Jeong Soo; Cho, Yeong Garp; Lee, Jung Hee; Shin, Jin Won

    2008-04-15

    This report details the technical requirements for the fabrication and installation of the removable shield for the Cold Neutron Research Facility (CNRF) in HANARO reactor hall. The removable shield is classified as non-nuclear safety (NNS), seismic category II, and quality class T. The main function of the removable shield is to do the biological shielding of neutrons and gamma from the CN port and the guides. The removable shield consists of block type walls and roofs that can be necessarily assembled, disassembled and moveable. These will be installed between the reactor pool wall and the CNS guide bunker in. This report describes technical requirements for the removable shield such as quality assurance, seismic analysis requirements, configuration, concrete compositions, fabrication and installation requirements, test and inspection, shipping, delivery, etc. Appendix is the technical specification of structural design and analysis. Attachments are composed of the technical specification for the fabrication of the removable shield, shielding design drawings and procurement quality requirements. These technical requirements will be provided to a contract for the manufacturing and installation.

  14. Analysis of the JASPER Program Radial Shield Attenuation Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Slater, C.O.

    1993-01-01

    The results of the analysis of the JASPER Program Radial Shield Attenuation Experiment are presented. The experiment was performed in 1986 at the ORNL Tower Shielding Facility. It is the first of six experiments in this cooperative Japanese and American program in support of shielding designs for advanced sodium-cooled reactors. Six different shielding configurations and subconfigurations thereof were studied. The configurations were calculated with the DOT-IV two-dimensional discrete ordinates radiation transport computer code using the R-Z geometry option, a symmetric S{sub 12} quadrature (96 directions), and cross sections from ENDF/B versions IV and V in either a 51- or 61-group structure. Auxiliary codes were used to compute detector responses and prepare cross sections and source input for the DOT-IV calculations. Calculated detector responses were compared with measured responses and the agreement was good to excellent in many cases. However, the agreement for configurations having thick steel or B{sub 4}C regions or for some very large configurations was fair to poor. The disagreement was attributed to cross-section data, broad-group structure, or high background in the measurements. In particular, it is shown that two cross-section sets for ``B give very different results for neutron transmission through the thick B{sub 4}C regions used in one set of experimental configurations. Implications for design calculations are given.

  15. Antireflectance coating on shielding window glasses using glacial acetic acid at ambient temperature

    International Nuclear Information System (INIS)

    Sathi Sasidharan, N.; Deshingkar, D.S.; Wattal, P.K.

    2006-01-01

    High density lead glasses having thickness of several centimeters and large dimensions are used as shielding windows in hot cells. To improve visibility, the reflection of light from its optically polished surfaces needs to be minimized to improve transmission as absorption of light in the thick glasses can not be avoided. Antireflectance coating of a material having low refractive index is required for this purpose. Selective leaching of lead at ambient temperature in glacial acetic acid develops a silica rich leached layer on glass surface. Since silica has low refractive index, the leached layer serves as antireflectance coating. Two optically polished discs of shielding window glasses were leached in glacial acetic acid at ambient temperature for 2, 5 and 10 days and their reflectance and transmittance spectra were taken to find effect of leaching. For transparent glass transmittance could be improved from 78.76% to 85.31% after 10 days leaching. Reflectance from the glass could be decreased from 12.48 to 11.67%. For coloured glass transmittance improved from 87.77% to 88.24% after 5 days leaching while reflectance decreased from 12.28% to 5.6% during same period. Based on data generated, 10 days leaching time is recommended for developing anti reflectance coating on transparent shielding window glass and 5 days for coloured shielding window glass. The procedure can be used for shielding windows of any dimensions by fabrication a PVC tank of slightly high dimensions and filling with acetic acid (author)

  16. Calculation analysis of the thickness of radiation shield for the RIA equipment IP10

    International Nuclear Information System (INIS)

    Benar Bukit; Kristiyanti; Hari Nurcahyadi

    2011-01-01

    Calculation Analysis has been performed on the thickness of radiation shield for the design of the Radioimmunoassay (RIA) IP10 counters using five detectors arranged in parallel. The calculation is intended to ensure that the radiation on each detector does not influence each other. The radiation shield is made of lead. The calculation of lead thickness was based on the principle of the lead plates absorptive power toward the gamma ray of a certain energy. which is the function of linear absorption coefficient and the material thickness. Assuming the use of Iodium-125(I-125) source with an activity 10 µCi, and expecting an absorptive power of 95%, calculations showed that the required lead thickness is equal to 0,013 cm. Since lead is soft and its availability in the market is limited, lead plate of 2 mm thickness are used instead, so that counting result for the detectors do not influence each other. (author)

  17. Radiation transmission data for radionuclides and materials relevant to brachytherapy facility shielding.

    Science.gov (United States)

    Papagiannis, P; Baltas, D; Granero, D; Pérez-Calatayud, J; Gimeno, J; Ballester, F; Venselaar, J L M

    2008-11-01

    To address the limited availability of radiation shielding data for brachytherapy as well as some disparity in existing data, Monte Carlo simulation was used to generate radiation transmission data for 60Co, 137CS, 198Au, 192Ir 169Yb, 170Tm, 131Cs, 125I, and 103pd photons through concrete, stainless steel, lead, as well as lead glass and baryte concrete. Results accounting for the oblique incidence of radiation to the barrier, spectral variation with barrier thickness, and broad beam conditions in a realistic geometry are compared to corresponding data in the literature in terms of the half value layer (HVL) and tenth value layer (TVL) indices. It is also shown that radiation shielding calculations using HVL or TVL values could overestimate or underestimate the barrier thickness required to achieve a certain reduction in radiation transmission. This questions the use of HVL or TVL indices instead of the actual transmission data. Therefore, a three-parameter model is fitted to results of this work to facilitate accurate and simple radiation shielding calculations.

  18. Muon shield requirements for ISABELLE at 400 GeV/c

    International Nuclear Information System (INIS)

    Ludlam, T.; Thorndike, A.M.

    1977-01-01

    A goodly portion of the ISABELLE ring lies above the existing contours of the land, and so a substantial earth berm is required to shield against penetrating muons which result from proton interactions within the ring. The size and shape of this shield is determined not only by the magnitude of expected proton losses from the circulating beams, but also by the geometry and magnetic structure of the machine, and the proximity of potential muon sources to the site boundary. The cost of constructing this berm is sufficiently great as to warrant detailed attention to the required shield thickness at each point around the ring. The report given updates previous discussions of the subject by incorporating the six-fold geometry and higher energy of the 400 GeV ISABELLE design, and taking advantage of a more refined study of the effects of magnetic deflection on the trajectories of muons produced within the lattice structure of the machine

  19. Radiation shielding properties of a novel cement–basalt mixture for nuclear energy applications

    Energy Technology Data Exchange (ETDEWEB)

    Ipbüker, Cagatay; Nulk, Helena; Gulik, Volodymyr [University of Tartu, Institute of Physics (Estonia); Biland, Alex [HHK Technologies, Houston (United States); Tkaczyk, Alan Henry, E-mail: alan@ut.ee [University of Tartu, Institute of Physics (Estonia)

    2015-04-01

    Highlights: • Basalt fiber is a relatively cheap material that can be used as reinforcement. • Gamma-ray attenuation remains relatively stable with addition of basalt fiber. • Neutron attenuation remains relatively stable with addition of basalt fiber. • Cement–basalt mixture has a good potential for use in nuclear energy applications. - Abstract: The radiation shielding properties of a new proposed building material, a novel cement–basalt fiber mixture (CBM), are investigated. The authors analyze the possibility of this material to be a viable substitute to outgoing materials in nuclear energy applications, which will lead to a further sustained development of nuclear energy in the future. This computational study involves four types of concrete with various amounts of basalt fiber in them. The gamma-ray shielding characteristics of proposed CBM material are investigated with the help of WinXCom program, whereas the neutron shielding characteristics are computed by the Serpent code. For gamma-ray shielding, we find that the attenuation coefficients of concretes with basalt fibers are not notably influenced by the addition of fibers. For neutron shielding, additional basalt fiber in mixture presents negligible effect on neutron radiation shielding. With respect to radiation shielding, it can be concluded that basalt fibers have good potential as an addition to heavyweight concrete for nuclear energy applications.

  20. Radiation shielding properties of a novel cement–basalt mixture for nuclear energy applications

    International Nuclear Information System (INIS)

    Ipbüker, Cagatay; Nulk, Helena; Gulik, Volodymyr; Biland, Alex; Tkaczyk, Alan Henry

    2015-01-01

    Highlights: • Basalt fiber is a relatively cheap material that can be used as reinforcement. • Gamma-ray attenuation remains relatively stable with addition of basalt fiber. • Neutron attenuation remains relatively stable with addition of basalt fiber. • Cement–basalt mixture has a good potential for use in nuclear energy applications. - Abstract: The radiation shielding properties of a new proposed building material, a novel cement–basalt fiber mixture (CBM), are investigated. The authors analyze the possibility of this material to be a viable substitute to outgoing materials in nuclear energy applications, which will lead to a further sustained development of nuclear energy in the future. This computational study involves four types of concrete with various amounts of basalt fiber in them. The gamma-ray shielding characteristics of proposed CBM material are investigated with the help of WinXCom program, whereas the neutron shielding characteristics are computed by the Serpent code. For gamma-ray shielding, we find that the attenuation coefficients of concretes with basalt fibers are not notably influenced by the addition of fibers. For neutron shielding, additional basalt fiber in mixture presents negligible effect on neutron radiation shielding. With respect to radiation shielding, it can be concluded that basalt fibers have good potential as an addition to heavyweight concrete for nuclear energy applications

  1. Innovative analytical competence. Optimization of shielding components and lifetime activation calculations

    Energy Technology Data Exchange (ETDEWEB)

    Boehlke, Steffen; Wortmann, Birgit; Aguilar, Arturo Lizon [STEAG Energy Services GmbH, Essen (Germany)

    2014-08-15

    Shielding and activation calculations always require a high level of engineering competence and powerful hard- and software tools. With the application of current methods often certain limits were reached in the past. The engineering work for optimization efforts regarding complex components with high shielding requirements exceeded the savings in material. With regard to activation the challenges in size of the geometric model and considered operation time rises constantly and pushes computing time beyond reasonable time frames. These challenges require the application of new and faster methodologies. The application of new and innovative methods is presented for a shielding optimization project to decrease the radiation level, to keep the dose rate limits, and to reduce the amount of used shielding material. In a second case a prediction of the activated materials with it's dose distribution in the surrounding area and classification of waste quantities in the structural materials of a nuclear reactor is presented. For the shielding project the preliminary design CAD model was imported into the software tool, several iterations were run and a significantly reduced radiation exposure together with a significant reduction in shieling material were achieved. For the activation calculations it could be demonstrated that it is possible to determine the activation, waste quantities and dose distribution for the structural materials of a nuclear reactor based on lifetime operational data within reasonable time frames.

  2. Analysis methods for Kevlar shield response to rotor fragments

    Science.gov (United States)

    Gerstle, J. H.

    1977-01-01

    Several empirical and analytical approaches to rotor burst shield sizing are compared and principal differences in metal and fabric dynamic behavior are discussed. The application of transient structural response computer programs to predict Kevlar containment limits is described. For preliminary shield sizing, present analytical methods are useful if insufficient test data for empirical modeling are available. To provide other information useful for engineering design, analytical methods require further developments in material characterization, failure criteria, loads definition, and post-impact fragment trajectory prediction.

  3. Location of the ovaries in girls from newborn to 18 years of age: reconsidering ovarian shielding

    International Nuclear Information System (INIS)

    Bardo, Dianna M.E.; Schenk, Kellie; Black, Michelle; Zaritzky, Mario F.

    2009-01-01

    Guidelines for ovarian shielding are to place a lead shield in the midline of the abdomen at the level of the umbilicus. However, the ovaries are routinely seen at other locations on all types of imaging examinations. To determine the position of the ovaries in girls, newborn to 18 years of age, in order to assess efficacy of ovarian shield placement. We identified 336 girls who underwent lumbar spine and pelvic MRI. Images were reviewed noting the position of the ovaries relative to anatomic landmarks: symphysis pubis, iliac crest and anterior superior iliac spine (ASIS). In 174 girls a total of 307 ovaries were visualized. The girls were divided into three age groups and analyzed together. Right and left ovaries were analyzed together. The mean, 95% confidence interval (CI), standard deviations and range were calculated. The ovaries lay at or below the iliac crest (the level of the umbilicus), most often just medial to the ASIS and above the pubic symphysis in girls of all ages. Current methods of shielding only the midline of the pelvis for the purpose of reducing radiation dose to the ovaries during radiographic imaging are ineffective given that the ovaries are almost always positioned laterally in the pelvis. Therefore current shielding techniques should be changed; lead ovarian shields should be placed in a lateral position or even abandoned if relevant anatomy will be obscured. (orig.)

  4. Shielding Studies for Reducing the associated Radiological Risks Due To Irradiated Low Enriched Uranium Foil

    International Nuclear Information System (INIS)

    Margeanu, C.A.

    2011-01-01

    Present work estimates the radiation dose rates corresponding to irradiated Low Enriched Uranium (20 wt % 235 U) foil as part of shielding studies for radiological risks reduction after irradiation inside TRIGA 14 MW Research Reactor in an investigation on 99 Mo production possibility. Post-Irradiation Examination Laboratory's cell shielding calculations have been performed; radiation source was obtained by using ORIGEN-S code with specific cross-sections libraries. Different post-irradiation cooling times have been considered, gamma dose rates being estimated by using MAVRIC module from Scale 6 programs package, for following exposure situations (relative to Pie cell): i) front side, ii) lateral side and iii) back side. Three different calculations were performed: a) without any protection shield between operator and cell, except for the cell stainless steel wall; b) with a Lead protection shield between operator and cell and c) with a depleted Uranium shield, located inside the cell in between the radiation source and cell window. Radiation dose rates to cell external wall surface and for other eight fixed distances from cell wall were estimated. To obtain a consistent set of solutions, the study was done for various Uranium foil weights and different Lead and depleted Uranium shields thicknesses. Calculations were focused to assure that the dose rate to an operator positioned at 60 cm working distance from the cell will not exceed 0.02 mSv/h, maximum allowed dose rate for professionally exposed personnel according to Romanian regulations.

  5. Gonad shielding in diagnostic radiology

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    The use of gonad shielding is an important radiation protection technique, intended to reduce unnecessary x-ray exposure of the gonads of patients from diagnostic x-ray procedures. The types of gonad shields in use are discussed as are the types of diagnostic examinations that should include gonad shielding. It was found that when properly used, most shields provided substantial gonad dose reductions

  6. Effects of Sm addition on electromagnetic interference shielding property of Mg-Zn-Zr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Chubin [Chongqing University, College of Materials Science and Engineering, National Engineering Research Center for Magnesium Alloy, Chongqing (China); Gannan Normal University, Jiangxi Provincial Engineering Research Center for Magnesium Alloy, Ganzhou (China); Pan, Fusheng; Chen, Xianhua [Chongqing University, College of Materials Science and Engineering, National Engineering Research Center for Magnesium Alloy, Chongqing (China); Luo, Ning [Gannan Normal University, Jiangxi Provincial Engineering Research Center for Magnesium Alloy, Ganzhou (China)

    2017-06-15

    The electromagnetic interference (EMI) shielding of Sm-containing magnesium alloys in the 30-1500 MHz testing frequency range was investigated by coaxial cable method. The results demonstrated that Mg-3Zn alloys displayed the best electromagnetic shielding property. When 0.5 wt% of Zr was added for crystal grain refinement, the shielding effectiveness (SE) was apparently reduced. The addition of the rare earth element Sm in ZK magnesium alloys can improve the electromagnetic interference shielding of magnesium alloys. The main reason for the differences in electromagnetic interference shielding of magnesium alloys was the change in conductivity. The addition of Zr in Mg-Zn alloys can refine the grains and consequently improve the grain boundary area significantly. Therefore, the number of irregularly arranged atoms at the grain boundaries increased, decreasing the conductivity of magnesium alloys and leading to a decrease in the electromagnetic interference shielding. Following the Sm addition, the Mg-Zn-Sm phase was precipitated at the grain boundaries and in cores. The precipitation of Sm-containing rare earth phases could consume the solid-soluted Zn atoms within the Mg, resulting in an increase in electrical conductivity and electromagnetic interference shielding improvement. (orig.)

  7. Pulse-echo ultrasonic inspection system for in-situ nondestructive inspection of Space Shuttle RCC heat shields.

    Energy Technology Data Exchange (ETDEWEB)

    Roach, Dennis Patrick; Walkington, Phillip D.; Rackow, Kirk A.

    2005-06-01

    The reinforced carbon-carbon (RCC) heat shield components on the Space Shuttle's wings must withstand harsh atmospheric reentry environments where the wing leading edge can reach temperatures of 3,000 F. Potential damage includes impact damage, micro cracks, oxidation in the silicon carbide-to-carbon-carbon layers, and interlaminar disbonds. Since accumulated damage in the thick, carbon-carbon and silicon-carbide layers of the heat shields can lead to catastrophic failure of the Shuttle's heat protection system, it was essential for NASA to institute an accurate health monitoring program. NASA's goal was to obtain turnkey inspection systems that could certify the integrity of the Shuttle heat shields prior to each mission. Because of the possibility of damaging the heat shields during removal, the NDI devices must be deployed without removing the leading edge panels from the wing. Recently, NASA selected a multi-method approach for inspecting the wing leading edge which includes eddy current, thermography, and ultrasonics. The complementary superposition of these three inspection techniques produces a rigorous Orbiter certification process that can reliably detect the array of flaws expected in the Shuttle's heat shields. Sandia Labs produced an in-situ ultrasonic inspection method while NASA Langley developed the eddy current and thermographic techniques. An extensive validation process, including blind inspections monitored by NASA officials, demonstrated the ability of these inspection systems to meet the accuracy, sensitivity, and reliability requirements. This report presents the ultrasonic NDI development process and the final hardware configuration. The work included the use of flight hardware and scrap heat shield panels to discover and overcome the obstacles associated with damage detection in the RCC material. Optimum combinations of custom ultrasonic probes and data analyses were merged with the inspection procedures needed to

  8. Engineering and Fabrication Considerations for Cost-Effective Space Reactor Shield Development

    International Nuclear Information System (INIS)

    Berg, Thomas A.; Disney, Richard K.

    2004-01-01

    Investment in developing nuclear power for space missions cannot be made on the basis of a single mission. Current efforts in the design and fabrication of the reactor module, including the reactor shield, must be cost-effective and take into account scalability and fabricability for planned and future missions. Engineering considerations for the shield need to accommodate passive thermal management, varying radiation levels and effects, and structural/mechanical issues. Considering these challenges, design principles and cost drivers specific to the engineering and fabrication of the reactor shield are presented that contribute to lower recurring mission costs

  9. Shielding tests for a new ship for the transport of spent nuclear fuels

    International Nuclear Information System (INIS)

    Ito, D.; Kitano, T.; Akiyama, H.; Ueki, K.; Sanui, T.

    1998-01-01

    a new ship for the transport of spent nuclear fuels which uses serpentine concrete as its major shielding material has been constructed. The shielding calculations are based on DOT3.5 code (CCC-276) and the DLC23). Experiments with Cf-252 and Co-60 sources were carried out to confirm the validity of this method of calculating the shielding effectiveness of serpentine concrete. In these experiments, neutron and gamma-ray dose equivalent rates were measured in various arrangements to simulate the shielding structures of the ship, the calculations for each arrangement were performed by this shielding calculation method. For both neutron and gamma-rays, the calculation results agreed with the experiments very well, confirming that this calculation method used in the ship's shielding design is valid. Two kinds of on-board gamma-ray shielding tests were performed to confirm the ship's actual shielding effectiveness. In one kind of test, gamma-ray dose equivalent rates were measured for each shielding wall using Co-60 sources. In the other kind of test, gamma-ray dose equivalent rates in the ship's accommodation area were measured when a strong Co-60 source was placed in a loaded shipping cask's position. In both gamma-ray shielding tests all measured dose equivalent rates were less than the calculated values, confirming that the ship's actual shielding is sufficient to meet safety requirements. (authors)

  10. New conceptual antenna with spiral structure and back Faraday shield for FWCD (fast wave current drive)

    International Nuclear Information System (INIS)

    Saigusa, M.; Moriyama, S.; Fujii, T.; Kimura, H.

    1994-01-01

    A new conceptual antenna, which we call as a spiral antenna, is proposed as a traveling wave antenna for fast wave current drive in tokamaks. The features of the spiral antenna are a sharp N z spectrum, easy impedance matching, N z controllable and good coupling. A back Faraday shield is proposed for improving the cooling design of Faraday shield and better antenna-plasma coupling. A helical support which is a compact and wide band support is proposed as a kind of quarter wave length stub supports. The RF properties of the spiral antenna and the back Faraday shield have been investigated by using mock-up antennas. The VSWR of spiral antenna is low at the wide frequency band from 15 MHz to 201 MHz. The back Faraday shield is effective for suppressing the RF toroidal electric field between adjacent currents straps. (author)

  11. Finite-element simulation of the performance of a superconducting meander structure shielding for a cryogenic current comparator

    Energy Technology Data Exchange (ETDEWEB)

    De Gersem, H., E-mail: degersem@temf.tu-darmstadt.de [Institut für Theorie Elektromagnetischer Felder, Technische Universität Darmstadt, Schlossgartenstraße 8, 64289 Darmstadt (Germany); Marsic, N.; Müller, W.F.O. [Institut für Theorie Elektromagnetischer Felder, Technische Universität Darmstadt, Schlossgartenstraße 8, 64289 Darmstadt (Germany); Kurian, F.; Sieber, T.; Schwickert, M. [GSI Helmholtzzentrum für Schwerionenforschung, Planckstraße 1, 64291 Darmstadt (Germany)

    2016-12-21

    The ferrite core and measuring coil of a cryogenic current comparator have to be shielded against external magnetic fields by a compact, efficient meander structure made of superconducting niobium. A design with minimized material and production costs is only feasible when a highly accurate magnetic field simulator is available. 3D field models become prohibitively large. The cylindrical symmetry of the devices motivates to develop a quasi-3D field solver, exploiting the symmetry while still capable of representing 3D field distributions.

  12. Theoretical and experimental estimation of the lead equivalent for some materials used in finishing of diagnostic x-ray rooms in Syria

    International Nuclear Information System (INIS)

    Shwekani, R.; Suman, H.; Takeyeddin, M.; Suleiman, J.

    2003-11-01

    This work aimed at estimating the lead equivalent values for finishing materials, which are frequently used in Syria. These materials are ceramic and marble. In the past, many studies were performed to estimate the lead equivalent values for different types of bricks, which are widely used in Syria. Therefore, this work could be considered as a follow up in order to be able to estimate the structural shielding of diagnostic X-ray rooms and accurately perform the shielding calculations to reduce unnecessary added shields. The work was done in two ways, theoretical using MCNP computer code and experimental in the secondary standard laboratory. The theoretical work was focused on generalizing the results scope to cover the real existing variations in the structure of the materials used in the finishing or the variations in the X-ray machines. Therefore, quantifying different sources of errors were strongly focused on using the methodology of sensitivity analysis. While, the experiment measurements were performed to make sure that their results will be within the error range produced by the theoretical study. The obtained results showed a strong correlation between theoretical and experimental data. (author)

  13. Gamma dose from activation of internal shields in IRIS reactor.

    Science.gov (United States)

    Agosteo, Stefano; Cammi, Antonio; Garlati, Luisella; Lombardi, Carlo; Padovani, Enrico

    2005-01-01

    The International Reactor Innovative and Secure is a modular pressurised water reactor with an integral design. This means that all the primary system components, such as the steam generators, pumps, pressuriser and control rod drive mechanisms, are located inside the reactor vessel, which requires a large diameter. For the sake of better reliability and safety, it is desirable to achieve the reduction of vessel embrittlement as well as the lowering of the dose beyond the vessel. The former can be easily accomplished by the presence of a wide downcomer, filled with water, which surrounds the core region, while the latter needs the presence of additional internal shields. An optimal shielding configuration is under investigation, for reducing the ex-vessel dose due to activated internals and for limiting the amount of the biological shielding. MCNP 4C calculations were performed to evaluate the neutron and the gamma dose during operation and the 60Co activation of various shields configurations. The gamma dose beyond the vessel from activation of its structural components was estimated in a shutdown condition, with the Monte Carlo code FLUKA 2002 and the MicroShield software. The results of the two codes are in agreement and show that the dose is sufficiently low, even without an additional shield.

  14. Gamma dose from activation of internal shields in IRIS reactor

    International Nuclear Information System (INIS)

    Agosteo, S.; Cammi, A.; Garlati, L.; Lombardi, C.; Padovani, E.

    2005-01-01

    The International Reactor Innovative and Secure is a modular pressurised water reactor with an integral design. This means that all the primary system components, such as the steam generators, pumps, pressurizer and control rod drive mechanisms, are located inside the reactor vessel, which requires a large diameter. For the sake of better reliability and safety, it is desirable to achieve the reduction of vessel embrittlement as well as the lowering of the dose beyond the vessel. The former can be easily accomplished by the presence of a wide downcomer, filled with water, which surrounds the core region, while the latter needs the presence of additional internal shields. An optimal shielding configuration is under investigation, for reducing the ex-vessel dose due to activated internals and for limiting the amount of the biological shielding. MCNP 4C calculations were performed to evaluate the neutron and the gamma dose during operation and the 60 Co activation of various shields configurations. The gamma dose beyond the vessel from activation of its structural components was estimated in a shutdown condition, with the Monte Carlo code FLUKA 2002 and the MicroShield software. The results of the two codes are in agreement and show that the dose is sufficiently low, even without an additional shield. (authors)

  15. Investigations on the Broadband Shielding Effectiveness of Metallized Glass Fiber

    National Research Council Canada - National Science Library

    Coburn, William

    1998-01-01

    ...) is an E-glass fiber metallized with Al and processed into a nonwoven mat. When formed into a mat, the MGFs lead to an effective sample conductivity, sigma eff, which is the parameter of interest for electromagnetic shielding in the RF region...

  16. Radiation shielding calculation using MCNP

    International Nuclear Information System (INIS)

    Masukawa, Fumihiro

    2001-01-01

    To verify the Monte Carlo code MCNP4A as a tool to generate the reference data in the shielding designs and the safety evaluations, various shielding benchmark experiments were analyzed using this code. These experiments were categorized in three types of the shielding subjects; bulk shielding, streaming, and skyshine. For the variance reduction technique, which is indispensable to get meaningful results with the Monte Carlo shielding calculation, we mainly used the weight window, the energy dependent Russian roulette and spitting. As a whole, our analyses performed enough small statistical errors and showed good agreements with these experiments. (author)

  17. MMW [multimegawatt] shielding design and analysis

    International Nuclear Information System (INIS)

    Olson, A.P.

    1988-01-01

    Reactor shielding for multimegawatt (MMW) space power must satisfy a mass constraint as well as performance specifications for neutron fluence and gamma dose. A minimum mass shield is helpful in attaining the launch mass goal for the entire vehicle, because the shield comprises about 1% to 2% of the total vehicle mass. In addition, the shield internal heating must produce tolerable temperatures. The analysis of shield performance for neutrons and gamma rays is emphasized. Topics addressed include cross section preparation for multigroup 2D S/sub n/-transport analyses, and the results of parametric design studies on shadow shield performance and mass versus key shield design variables such as cone angle, number, placement, and thickness of layers of tungsten, and shield top radius. Finally, adjoint methods are applied to the shield in order to spatially map its relative contribution to dose reduction, and to provide insight into further design optimization. 7 refs., 2 figs., 3 tabs

  18. Determination of material and its thickness for Cs-137 gamma source shielding

    International Nuclear Information System (INIS)

    Tukiman

    2008-01-01

    Its has been determined the shielding material and its thickness necessarily conducted due to every material will have different half-thickness characteristics, and by the selection a suitable material and its thickness will be obtained. Half-thickness of any material is the ability of the material at a certain thickness to absorb any radiation intensity so that the intensity becomes half of its source. Sample materials to be used are concrete, wood, and lead with their thickness varied. From experiment data and theoretical computation can be concluded that lead is the suitable material for shielding with the value of HVT for gamma radiation 0,732 cm. For wood and concrete will give half-thickness of 11,0 cm and 3,164 cm respectively. (author)

  19. Self-shielding characteristics of aqueous self-cooled blankets for next generation fusion devices

    International Nuclear Information System (INIS)

    Pelloni, S.; Cheng, E.T.; Embrechts, M.J.

    1987-11-01

    The present study examines self-shielding characteristics for two aqueous self-cooled tritium producing driver blankets for next generation fusion devices. The aqueous Self-Cooled Blanket concept (ASCB) is a very simple blanket concept that relies on just structural material and coolant. Lithium compounds are dissolved in water to provide for tritium production. An ASCB driver blanket would provide a low technology and low temperature environment for blanket test modules in a next generation fusion reactor. The primary functions of such a blanket would be shielding, energy removal and tritium production. One driver blanket considered in this study concept relates to the one proposed for the Next European Torus (NET), while the second concept is indicative for the inboard shield design for the Engineering Test Reactor proposed by the USA (TIBER II/ETR). The driver blanket for NET is based on stainless steel for the structural material and aqueous solution, while the inboard shielding blanket for TIBER II/ETR is based on a tungsten/aqueous solution combination. The purpose of this study is to investigate self-shielding and heterogeneity effects in aqueous self-cooled blankets. It is found that no significant gains in tritium breeding can be achieved in the stainless steel blanket if spatial and energy self-shielding effects are considered, and the heterogeneity effects are also insignificant. The tungsten blanket shows a 5 percent increase in tritium production in the shielding blanket when energy and spatial self-shielding effects are accounted for. However, the tungsten blanket shows a drastic increase in the tritium breeding ratio due to heterogeneity effects. (author) 17 refs., 9 figs., 9 tabs

  20. Dependences of microstructure on electromagnetic interference shielding properties of nano-layered Ti3AlC2 ceramics.

    Science.gov (United States)

    Tan, Yongqiang; Luo, Heng; Zhou, Xiaosong; Peng, Shuming; Zhang, Haibin

    2018-05-21

    The microstructure dependent electromagnetic interference (EMI) shielding properties of nano-layered Ti 3 AlC 2 ceramics were presented in this study by comparing the shielding properties of various Ti 3 AlC 2 ceramics with distinct microstructures. Results indicate that Ti 3 AlC 2 ceramics with dense microstructure and coarse grains are more favourable for superior EMI shielding efficiency. High EMI shielding effectiveness over 40 dB at the whole Ku-band frequency range was achieved in Ti 3 AlC 2 ceramics by microstructure optimization, and the high shielding effectiveness were well maintained up to 600 °C. A further investigation reveals that only the absorption loss displays variations upon modifying microstructure by allowing more extensive multiple reflections in coarse layered grains. Moreover, the absorption loss of Ti 3 AlC 2 was found to be much higher than those of highly conductive TiC ceramics without layered structure. These results demonstrate that nano-layered MAX phase ceramics are promising candidates of high-temperature structural EMI shielding materials and provide insightful suggestions for achieving high EMI shielding efficiency in other ceramic-based shielding materials.

  1. 3-dimensional shielding design for a spallation neutron source facility in the high-intensity proton accelerator project

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, Masaya; Maekawa, Fujio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    Evaluation of shielding performance for a 1 MW spallation neutron source facility in the Materials and Life Science Facility being constructed in the High-Intensity Proton Accelerator Project (J-PARC) is important from a viewpoint of radiation safety and optimization of arrangement of components. This report describes evaluated results for the shielding performance with modeling three-dimensionally whole structural components including gaps between them in detail. A Monte Carlo calculation method with MCNPX2.2.6 code and LA-150 library was adopted. Streaming and void effects, optimization of shield for cost reduction and optimization of arrangement of structures such as shutters were investigated. The streaming effects were investigated quantitatively by changing the detailed structure of components and gap widths built into the calculation model. Horizontal required shield thicknesses were ranged from about 6.5 m to 7.5 m as a function of neutron beam line angles. A shutter mechanism for a horizontal neutron reflectometer that was directed downward was devised, and it was shown that the shielding performance of the shutter was acceptable. An optimal biological shield configuration was finally determined according to the calculated results. (author)

  2. Shielding repair of N.S. Mutsu and related safety features

    International Nuclear Information System (INIS)

    Kishimoto, K.; Miyakoshi, J.

    1978-01-01

    The abnormal radiation level observed on the upper deck of N.S. Mutsu was caused by neutrons streaming through an annular air gap between the reactor pressure vessel and the primary shield. In order to lower this level, a modification of shielding has been planned, for which a shielding mock-up experiment was carried. The foregoing modifications brought some change to the expected behavior of the reactor plant under ship accident situations, and studies were performed to verify plant safety, such as calculations to determine containment vessel integrity and decay heat removal after sinking, and calculations supported by experiment to ascertain the structural strength of the double bottom upon stranding of the ship

  3. Evaluation of the Prevalence and Utility of Gonad Shielding in Pediatrics Undergoing Pelvic X-Ray

    Directory of Open Access Journals (Sweden)

    Vahid Karami

    2016-11-01

    Full Text Available Background: Gonad shielding has been recommended during pelvic x-rays since the 1950s. The popular method of gonad shielding is placement a lead shield in the midline of the pelvis. The aim of this study was to evaluate the prevalence and utility of gonad shielding in pediatrics undergoing pelvic x-rays.Materials and MethodsFollowing study approval, we retrospectively retrieved data from the digital image library of ten radiology depertments of Khuzestan provience-Iran to identify pediatric patients who underwent pelvic x-ray (anteriorposterior [AP] view. All the images were reviewed for the probable evidence of gonad shield. If there was evidence of shielding, the accuracy positioning of the shield was also investigated by a single assistant radiologist.ResultsIn all 1745 pelvic x-rays (942 girls and 803 boys were identified of which the shield was present in 51 (5.41% radiographs of girls and 132 (16.43% radiographs of boys. When a shield was present; the shields has adequate positioning only in 8 (15.68% radiographs in girls and 59 radiographs in boys. Inaccurate placement and absence of gonad shields were more common in girls than the boys. Due to the shield has concealed the anatomical criteria of the pelvis, retakes of the examination was required in 11 (21.56% radiographs of girls and 14 (10.6% radiographs of boys.ConclusionThe current methods of gonad shielding in girls pelvic x-ray was not effective nor is justifiable. We  no longer advocate of gonad shielding during girls pelvic x-ray. However in boys it is controversial and depends on the skill and effort of radiographers.

  4. LOFT shield tank steady state temperatures with addition of gamma and neutron shielding

    International Nuclear Information System (INIS)

    Kyllingstad, G.

    1977-01-01

    The effect of introducing a neutron and gamma shield into the annulus between the reactor vessel and the shield tank is analyzed. This addition has been proposed in order to intercept neutron streaming up the annulus during nuclear operations. Its installation will require removal of approximately 20- 1 / 2 inches of stainless steel foil insulation at the top of the annulus. The resulting conduction path is believed to result in increased water temperatures within the shield tank, possibly beyond the 150 0 F limit, and/or cooling of the reactor vessel nozzles such that adverse thermal stresses would be generated. A two dimensional thermal analysis using the finite element code COUPLE/MOD2 was done for the shield tank system illustrated in the figure (1). The reactor was assumed to be at full power, 55 MW (th), with a loop flow rate of 2.15 x 10 6 lbm/hr (268.4 kg/s) at 2250 psi (15.51 MPa). Calculations indicate a steady state shield tank water temperature of 140 0 F (60 0 C). This is below the 150 0 F (65.56 0 C) limit. Also, no significant changes in thermal gradients within the nozzle or reactor vessel wall are generated. A spacer between the gamma shield and the shield tank is recommended, however, in order to ensure free air circulation through the annulus

  5. Production yield of produced radioisotopes from 100 MeV proton beam on lead target for shielding analysis of large accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Oranj, Leila Mokhtari; Oh, Joo Hee; Jung, Nam Suk; Bae, O Ryun; Lee, Hee Seock [Div. of Advanced Nuclear Engineering, POSTECH, Pohang (Korea, Republic of)

    2014-11-15

    In this work, the production yield of major shielding material, a lead, was investigated using 100 MeV protons of KOMAC accelerator facility. For the analysis of the experimental data, the activity has been calculated using the FLUKA Monte Carlo code and analytical methods. The cross section data and the stopping power in the irradiated assembly were calculated by TALYS and SRIM codes in the analytical method, respectively. Consequently, the experimental production yield of produced radioisotopes was compared with the data that are based on Monte Carlo calculations and analytical studies. In this research, the {sup nat}Pb(p, x) reaction was studied using experimental measurements, Monte Carlo simulations and analytical methods. Rereading to the experimental measurements, we demonstrate that both Monte Carlo simulation and analytical methods could be useful tools for the estimation of production yield of this reaction.

  6. Production yield of produced radioisotopes from 100 MeV proton beam on lead target for shielding analysis of large accelerator

    International Nuclear Information System (INIS)

    Oranj, Leila Mokhtari; Oh, Joo Hee; Jung, Nam Suk; Bae, O Ryun; Lee, Hee Seock

    2014-01-01

    In this work, the production yield of major shielding material, a lead, was investigated using 100 MeV protons of KOMAC accelerator facility. For the analysis of the experimental data, the activity has been calculated using the FLUKA Monte Carlo code and analytical methods. The cross section data and the stopping power in the irradiated assembly were calculated by TALYS and SRIM codes in the analytical method, respectively. Consequently, the experimental production yield of produced radioisotopes was compared with the data that are based on Monte Carlo calculations and analytical studies. In this research, the nat Pb(p, x) reaction was studied using experimental measurements, Monte Carlo simulations and analytical methods. Rereading to the experimental measurements, we demonstrate that both Monte Carlo simulation and analytical methods could be useful tools for the estimation of production yield of this reaction

  7. Shielding designs and tests of a new exclusive ship for transporting spent nuclear fuels

    International Nuclear Information System (INIS)

    Ono, M.; Ito, D.; Kitano, T.; Ueki, K.; Akiyama, H.; Obara, I.; Sanui, T.

    2000-01-01

    The Rokuei-Maru, a ship built specially for the transport of spent nuclear fuels in casks, was launched April in 1996. She is the first ship to comply with special Japanese regulations, KAISA 520, based on the INF code. DOT3.5 and MCNP-4A were used for the evaluation of dose equivalent rates of her shielding structures. On-board gamma-ray shielding tests were executed to confirm the effectiveness of the ship's shielding performance. The tests confirmed that effective shielding has been achieved and the dose equivalent rate in the accommodation and other inhabited spaces is sufficiently lower than the regulated limitations. This was achieved by employing the appropriate calculation methods and shielding materials. (author)

  8. Structural evaluation of the Shippingport Reactor Pressure Vessel and Neutron Shield Tank package for impact and puncture loads

    International Nuclear Information System (INIS)

    Fischer, L.E.; Chou, C.K.; Lo, T.; Schwartz, M.W.

    1988-06-01

    A structural evaluation of Shippingport Reactor Pressure Vessel and Neutron Shield Tank package for impact and puncture loads under the normal and hypothetical accident conditions of 10 CFR 71 was performed. Component performance criteria for the Shippingport package and the corresponding structural acceptance criteria for these components were developed based on a review of the package geometry, the planned transport environment, and the external radiation standards and dispersal limits of 10 CFR 71. The evaluation was performed using structural analysis methods. A demonstration combining simplified model tests and nonlinear finite element analyses was made to substantiate the structural analysis methods used to evaluate the Shippingport package. The package was analyzed and the results indicate that the package meets external radiation standards and release limits of 10 CFR 71. 13 refs., 50 figs., 19 tabs

  9. Reduction of scatter radiation during transradial percutaneous coronary angiography: a randomized trial using a lead-free radiation shield.

    Science.gov (United States)

    Politi, Luigi; Biondi-Zoccai, Giuseppe; Nocetti, Luca; Costi, Tiziana; Monopoli, Daniel; Rossi, Rosario; Sgura, Fabio; Modena, Maria Grazia; Sangiorgi, Giuseppe M

    2012-01-01

    Occupational radiation exposure is a growing problem due to the increasing number and complexity of interventional procedures performed. Radial artery access has reduced the number of complications at the price of longer procedure duration. Radpad® scatter protection is a sterile, disposable bismuth-barium radiation shield drape that should be able to decrease the dose of operator radiation during diagnostic and interventional procedures. Such radiation shield has never been tested in a randomized study in humans. Sixty consecutive patients undergoing coronary angiography by radial approach were randomized 1:1 to Radpad use versus no radiation shield protection. The sterile shield was placed around the area of right radial artery sheath insertion and extended medially to the patient trunk. All diagnostic procedures were performed by the same operator to reduce variability in radiation absorption. Radiation exposure was measured blindly using thermoluminescence dosimeters positioned at the operator's chest, left eye, left wrist, and thyroid. Despite similar fluoroscopy time (3.52 ± 2.71 min vs. 3.46 ± 2.77 min, P = 0.898) and total examination dose (50.5 ± 30.7 vs. 45.8 ± 18.0 Gycm(2), P = 0.231), the mean total radiation exposure to the operator was significantly lower when Radpad was utilized (282.8 ± 32.55 μSv vs. 367.8 ± 105.4 μSv, P Radpad utilization at all body locations ranging from 13 to 34% reduction. This first-in-men randomized trial demonstrates that Radpad significantly reduces occupational radiation exposure during coronary angiography performed through right radial artery access. Copyright © 2011 Wiley Periodicals, Inc.

  10. Specialty glass development for radiation shielding windows and nuclear waste immobilization

    International Nuclear Information System (INIS)

    Mandal, S.; Ghorui, S.; Roy Chowdhury, A.; Sen, R.; Chakraborty, A.K.; Sen, S.; Maiti, H.S.

    2015-01-01

    The technology of two important varieties of specialty glasses, namely high density Radiation Shielding Window (RSW) glass and specialty glass beads of borosilicate composition have been successfully developed in CGCRI with an aim to meet the countries requirement. Radiation Shielding Windows used in nuclear installations, are viewing devices, which allow direct viewing into radioactive areas while still providing adequate protection to the operating personnel. The glass blocks are stabilized against damage from radiation by introducing cerium in definite proportions. Considering the essentially of developing an indigenous technology to make the country self-sufficient for this critical item, CGCRI has taken up a major programme to develop high lead containing glasses required for RSWs under a MoD with BARC. On the other hand, the specialty glass bead of specific composition and properties is a critical material required for management of radioactive waste in a closed nuclear fuel cycle that is followed by India. During reprocessing of the spent nuclear fuel, high level radio-active liquid waste (HLW) is produced containing unwanted radio isotopes some of which remain radioactive for thousands of years. The need is to immobilize them within a molecular structure so that they will not come out and be released to the ambience and thereby needs to be resolved if nuclear power is to make a significant contribution to the country's power requirement. Borosilicate glass has emerged as the material of choice for immobilization due to its unique random network structure

  11. Low background gamma ray spectrometer using the anticoincidence shield technique at KAERI

    International Nuclear Information System (INIS)

    Byun, Jong In; Choi, Yun Ho; Kwak, Seung Im; Hwang, Han Yull; Chung, Kun Ho; Choi, Geun Sik; Park, Doo Won; Lee, Chang Woo

    2002-01-01

    We develop a ultra-low background gamma ray spectrometer, using active and passive shielding technique at the same time. Cosmic ray induced background is suppressed by means of active shield devices consisting of plastic scintillating plates of 50 mm thick and anti-coincidence electronic system. The shield is made of 150 mm thick walls of very low activity lead, especially 20 mm with activity of -1 and 0.36 s -1 with and without active shield, respectively, on the regions from 50 keV to 3 MeV. The detection efficiency curve has been precisely measured for regions from 80 keV to 2 MeV with a 10 3 ml marinelli beaker sample, made with calibrated mixed-sources consists of 109 Cd, 57 Co, 139 Ce, 203 Hg, 113 Sn, 85 Sr, 137 Cs, 60 Co and 88 Y. The virtues of the method are demonstrated by applying on experiment that requires the lowest detection limit

  12. Theoretical evaluation of self-shielding factors due to scattering resonances in foils

    International Nuclear Information System (INIS)

    Selander, W.N.

    1960-06-01

    A semi-analytical method is given for evaluating self-shielding factors for activation measurements which use thin foils having neutron scattering resonances. The energy loss by scattering in the foil is taken into account. The energy-dependent neutron angular distribution is expanded as a double series, the coefficients of which are (energy dependent) solutions of an infinite set of coupled integral equations. These are truncated in